A key falls from a bridge that is 45 m above the water. It falls directly into a model boat, moving with constant velocity, that is 12 m from the point of impact when the key is re- leased. What is the speed of the boat

Answers

Answer 1

Answer:

4m/s

Explanation:

The motion is in downward direction, and the boat is moving with constant velocity, the position of the boat horizontally is 12m before the key fall.

The height difference "h"= ( y- y°)= 45 m

We can determine the needed time the key requires to reach the water using the expression from Newton's law

h= v(o) + 1/2 at^2

g= acceleration due to gravity= 9.8m/s^2

h= v(o) + 1/2 gt^2 -------------------------eqn*)

V(o)= 0 for the key= initial velocity

h= height that the key falls= 45m

If we substitute the above values into eqn(*) we have

We can make t^2 subject of the formula since v(0)= 0

t^2= h/(1/2 g)

= 45/(1/2× 9.8)

t^2= 45/4.9=9.18

t= √9.18

t=3.03 secs

Since the boat was moving with constant velocity,

Then Velocity= distance/ time

= 12/3.03

Velocity= 4m/s

Hence, the speed of the boat is 4m/s

Answer 2

Answer:

The person above me is correct. The speed of the boat is 3.6363m/s, or also 4m/s.

We know these following values from the key:

d = 45 , g = -9.8 (its because its falling) , vi = 0

With this, we can plug and chug using kinematic equations.

Doing so will get you 29.69 for Vf and 3.03 for time.

Now, we want the speed from the boat -- speed is defined as the distance over time. We know the distance from the boat is 12m, but now we know the time, which is 3.03.

-This time is correct because we know the boat was at "0m" when the key was at the start, but after it dropped, it was at 12m. So by finding out the time it took for the key to drop, it also tells us the amount of time it took the boat to travel 12m.

So this means we can divide 12m by 3.03s, or you can round it to 3. Whatever really works;

12/3.03 should get you something like 3.63 repeating

if you rounded, you will get 12/3, which is 4.


Related Questions

What’s the kinetic energy of the object? Use. Erica is competing in the shot put event at a track meet. She hurls a shot with a mass of 4 kilograms at a speed of 9 meters/second. The shot’s kinetic energy is_____ joules.

Answers

Answer:

4 kilograms

Explanation:

The diameter of Circle A is _________. EF AG EG FG

Answers

Answer:

The diameter is EF

Explanation:

Given

Circle A (See attachment)

Required

Determine the line that represents the diameter

First, it should be noted that the diameter of a circle is always a straight line.

From the attachment, the circle has the following straight lines:

E FE AA GA F

It should also be noted that the diameter passes through the center of a circle and divides it into two congruent parts.

From the list of straight lines above, only line EF satisfy this property

Hence, the diameter of the circle is line EF.

i think EF would be your answer.

Uses of Photodiode.State the 8 uses of phototide...................​

Answers

Answer:

Photodiodes are used in consumer electronics devices such as compact disc players, smoke detectors, medical devices and the receivers for infrared remote control devices used to control equipment from televisions to air conditioners. For many applications either photodiodes or photoconductors may be used.

if you know the amplitude of a wave, you know the distance from?

Answers

Answer:

As waves travel, they set up patterns of disturbance. The amplitude of a wave is its maximum disturbance from rest (its undisturbed position). It is important to note that the amplitude is not the distance between the top and bottom of a wave but is always measured from the rest position. This is a common exam mistake.

Explanation:

Jonas throws a ball up into the air. On its trip upward, the ball's velocity goes from 9.1 m/s to 0 m/s. On its trip downward, the ball's velocity goes from 0 m/s to -9.1 m/s. Did gravity do any work on the ball during the trip upward? Did gravity do any work on the trip downward? Justify your answer.

Answers

Answer:

1) Yes, the work done by gravity during the trip upward is -41.405·m J

2) Yes, the work done by gravity on the ball during the trip downward = 41.405·m J

Explanation:

The given parameters are;

The initial velocity of the ball on the way up = 9.1 m/s

The final velocity of the ball on the way up = 0 m/s

The initial velocity of the ball on its trip downward = 0 m/s

The final velocity of the ball on its trip downward = 9.1 m/s

1) The work done by gravity on the trip upward = The change in kinetic energy of the ball

The change in kinetic energy of the ball = 1/2 × m × 9.1² = -41.405·m J, given that the initial kinetic energy is 41.405·m J and the final kinetic energy is  J

Where;

m = The mass of the ball

Therefore, the work done by gravity during the trip upward = -41.405·m J

2) Similarly gravity does work on the ball during the trip downward = 41.405·m J.

What is the chemical formula for silver and oxygen

Answers

Answer:Ag2 O.

The formula for silver oxide is Ag2 O.

Explanation: one silver atom gives up an electron resulting in a +1 ion. Each oxygen atom requires two electrons to be stable.

List the three main things necessary to build an electromagnet.

Answers

Answer:

Electromagnets are special types of magnets that are made by passing current through coils of wire. To make an electromagnet, the minimum requirements are:

1. A nail (usually made of iron, steel or zinc)

2. Dry cell batteries

3. Wire (Usually copper wire)

Other things could be:

1. Electric tape to hold both ends of the wire properly at the battery terminals.

2. Scissors to cut the wire into desired length.

3. Iron fillings for testing purposes.

Please help!

A pulley system is hanged in a lift as shown below in the
figure. A and B are two masses each having m and 2m mass
respectively. If d is the distance from the floor to B and the
lift starts to move with acceleration a, the time taken by B to reach the floor is,
1)
[tex] \sqrt{ \frac{6d}{(g + a)} } [/tex]
2)
[tex]\sqrt{ \frac{6d}{g} }[/tex]
3)
[tex]\sqrt{ \frac{6d}{(g - a)} }[/tex]
4)
[tex] \frac{6d}{( g+ a)} [/tex]
5)
[tex]\sqrt{ \frac{2d}{(g + a)} }[/tex]

Answers

Answer:

B

Explanation:

Find the acceleration of the system

m2>m1

further m2 = 2m

and m1 = m

The acceleration is going to be the downward force created by m2 divided by the total mass (m2 + m2)

a = (m2*g - m1*g) / (m1 + m2)

a = (2m - m)*g/ (2m + m)

a = m * g/3m

a = 1/3 * g

Formula for time

Givens

distance := d

acceleration : = a  

vi = 0

Kinematic Formula

d = vi * t + 1/2 a t^2

Solution

d = 0 + 1/2 * 1/3 g  * t^2

6d = g * t^2

t^2 = 6d/g

t = √(6d/g)

Answer.

B

PLEASE HELP, MAJOR, brainest if correct

Answers

The answer is D hope this helps :D
I believe the answer is D

Assume that Michael's teacher has a rule that if a student talks out-of-turn three times in one day, that student must stay in for recess for the
rest of the week. Which of the following methods is she using to control student behavior?

a. folkway
b. sociobiology
c. informal sanction
d. formal sanction

Answers

D sorry if I get y’all wrong

Write the chemical formula and chemical name for two phosphorus and four fluorine.

Answers

Answer:

2 moles of phosphorus difluoride

2PFsubscript2

I hope it will be useful.

Why do adults make bigger splashes when they jump into swimming pools than small children?

Answers

Answer:

it bc the adults are bigger then us kid so when they dip in the pool it makes bigger splashes

Explanation:

A car that experiences no frictional force is started and caused to move. For the car to continue in that motion, the gas pedal would have to be used:

Answers

Explanation:

Gas pedal is not required to used on friction less surface. On a friction less surface once the car is started and caused to move, car continues to move with same velocity as there is no opposing force. Therefore, no pressing of gas pedal required. However, this situation is not possible in real life, as friction is always present.

****PLEASE HELP**** THERE ARE TWO QUESTIONS (ITS EASY)

Answers

but I think it's a and f

and

b and e

The Earth's _____
is what gives us day and night

1. Orbit
2. Rotation
3.Revolution

Answers

Answer:

rotation

Explanation:

............................

Answer: 2nd option, Rotation

I hope this helps, and Stay Safe! :)

State the hypothesis of this experiment​

Answers

How about: If mass is increased starting at 100 grams and 10 minutes, then the time will increase by 10 minutes by each 100g increase.

A car’s brakes decelerate it at a rate of -1.70 m/s2. What is the time, in seconds, required to slow the car from 15 m/s to 9.0 m/s?

Answers

Answer:

t = 3.52 s

Explanation:

Given that,

The deceleration of a car is, a = -1.7 m/s²

The initial velocity of the car, u = 15 m/s

Final velocity of the car, v = 9 m/s

We need to find the time that is required to slow the car from 15 m/s to 9 m/s. The definition of acceleration is :

[tex]a=\dfrac{v-u}{t}\\\\t=\dfrac{v-u}{a}\\\\t=\dfrac{9-15}{-1.7}\\\\t=3.52\ s[/tex]

So, it will take 3.52 seconds to slow the car from 15 m/s to 9 m/s.

how can a simple machine lift a heavy load with smaller effort​

Answers

Answer:

The axle is fixed to a frame or a block. The pulley is normally fixed to a support above the load. The load is tied to one end of the rope and the effort is applied at the other end. Such a pulley makes our work easier by simply changing the direction of the force, i.e. a load is lifted up using a downward effort.

May be this will help U

Answer:

The axle is fixed to a frame or a block. The pulley is normally fixed to a support above the load. The load is tied to one end of the rope and the effort is applied at the other end. Such a pulley makes our work easier by simply changing the direction of the force, i.e. a load is lifted up using a downward effort

Explanation:

The tension of a guitar string is increased by 40%. By what factor odes the fundamental frequency of vibration change? a. 1.13 b. 1.18 c. 1.06 d. 1.09 e. 1.24

Answers

Answer:

b. 1.18

Explanation:

The fundamental frequency in string is expressed as;

F1 = 1/2L√T/m .... 1

L is the length of the string

T is the tension

m is the mass per unit length

If the tension is increased by 40%, the new tension will be;

T2 = T + 40%T

T2 = T + 0.4T

T2 = 1.4T

The new fundamental frequency will be;

F2 = 1/2L√1.4T/m ..... 2

Divide 1 by 2;

F2/F = (1/2L√1.4T/m)/1/2L√T/m)+

F2/F = √1.4T/m ÷ √T/m

F2/F = √1.4T/√m ×√m/√T

F2/F = √1.4T/√T

F2/F = 1.18√T/√T

F2/F = 1.18

F2 = 1.18F

Hence the fundamental frequency of vibration changes by a factor of 1.18

Why does it take more force to get a resting object to move than it does to keep
a moving object going? (Hint: answer using ideas about microscopic
interactions) *

Answers

Answer:

Objects have a natural tendency to resist change. ... Heavier objects (greater mass) resist change more than lighter objects. Example: Pushing a bicycle or a Cadillac, or stopping them once moving. The more massive the object (more inertia) the harder it is to start or stop.

A car hits a tree and doesn’t stop, but keeps going until severely damaged. This is because of _____.

Answers

Answer:inertia

Explanation:

A car hits a tree and doesn’t stop, but keeps going until severely damaged. This is because of the principle of Inertia.

What is newton's first law of motion?

It states that" When a body s at rest it remains at rest, and IF the body is in motion It remains in motion until an external force is applied to that object."

i.e

If F=0, Then v= constant

and when that constant =0 then the body is at rest.

Where F= force

v = velocity.

Inertia is the tendency of an object to resist changes in its state of motion. In this case, the car was moving at a certain speed before it hit the tree, and because of its inertia, it continued to move forward even after the collision with the tree.

The car only stopped when another force acted on it, such as the force of the tree, or the force of friction with the ground, which slowed it down and eventually brought it to a stop. The severe damage to the car was a result of the force of the impact, which was a combination of the car's speed and its mass.

Hence the car does not stop because of the principle of inertia.

To learn more about Inertia click:

https://brainly.com/question/3268780

#SPJ3

When a capacitor, in RC circuit, is fully charged, the current through the resistor is Select one: zero if it is the only capacitor, but maximum if there is another capacitor in series with it. At its maximum value. Greater than the current in a resistor that is farther from the battery than the capacitor. Zero. Equal to the current in a resistive circuit in parallel with the capacitor circuit.

Answers

Answer:

The correct option is "Zero". A further explanation is given below.

Explanation:

As we know,

The capacitor is given by:

⇒ [tex]Q=C\times V[/tex]

Rate of change with respect to the time will be:

⇒ [tex]\frac{dQ}{dt}=C\times \frac{dV}{dt}[/tex]

Now,

It is mentioned in the question that the capacitor is completely charged, then

⇒ [tex]\frac{dV}{dt}=0[/tex]

i.e.,

⇒ [tex]\frac{dQ}{dt}=0[/tex]

All other choices available aren't related to that same scenario in question. So the answer above is the perfect one.

Calculate the momentum of a 32 kg eagle diving down to the water to catch a fish. During the dive, the eagle
travels 100 m in 10 seconds. Show your work

Answers

The eagle momentum : 320 kg.m/s

Further explanation

Given

mass = 32 kg

d = 100 m

t = 10 s

Required

The momentum

Solution

The velocity of the eagle :

[tex]\tt v=\dfrac{d}{t}\\\\v=\dfrac{100}{10}=10~m/s[/tex]

The momentum (P) :

[tex]\tt P=m\times v\\\\P=32\times 10\\\\P=320~kg.m/s[/tex]

when the mass of an object is increased it would decrease its acceleration in the force is left alone

Answers

Answer:

See the explanation below.

Explanation:

This analysis can be easily deduced by means of Newton's second law which tells us that the sum of the forces or the total force on a body is equal to the product of mass by acceleration.

∑F = m*a

where:

F = total force [N]

m = mass [kg]

a = acceleration [m/s²]

We must clear the acceleration value.

[tex]a=\frac{F}{m}[/tex]

We see that the term of the mass is in the denominator, so that if the value of the mass is increased the acceleration decreases, since they are inversely proportional.

What is the net force of the object below
A. 17 N right
B. 0 N
C. 3 N right
D. 3 N left

Answers

The answer to this question is C

Answer:

Concept: Physics

So we have forces in the Fx planeWe do sum of Fx= 0 Next we establish F-f So 10N- 7N = 3N to the right

2. __________is the pressure exerted by the layer of air around the Earth

Answers

Answer:

Atmospheric Pressure

Explanation:

can anyone help, i need help with this as well.

Answers

Answer:

B

Explanation:

I think this one is correct

c it is a answer of this question

how much force is needed to accelerate a 48 kg object to 3 m/s²​

Answers

Answer:

144 N

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 48 × 3

We have the final answer as

144 N

Hope this helps you

a 10-kg box is sitting at rest on a table. What is the net force acting on the box?

Answers

Answer:

the net force /resultant force is 0N

Explanation:

this is because newton's first law states that when there was no resultant force, the object will continue in its state of rest or uniform motion in a straight line.

as a result, the box is at rest. this the net for certain which is the resultant force is 0N, this doesn't mean that there is no force, it is just that the total force (after subtracting) is 0N

hope this helps,

Explain what happen to pressure exerted by air in the tyre if the temperature of tyre increases

Answers

Answer:

See the answer below

Explanation:

According to Amonton's law, the pressure of a gas is directly proportional to the temperature of its molecules given that the volume remains constant.

Hence, if the temperature of a tyre increases, heat is transferred to the air molecules within the tyre leading to an increase in the air temperature. The air thus exerts more pressure on the tyre in agreement with Amonton's law.

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