Answer:
The work required is -515,872.5 J
Explanation:
Work is defined in physics as the force that is applied to a body to move it from one point to another.
The total work W done on an object to move from one position A to another B is equal to the change in the kinetic energy of the object. That is, work is also defined as the change in the kinetic energy of an object.
Kinetic energy (Ec) depends on the mass and speed of the body. This energy is calculated by the expression:

where kinetic energy is measured in Joules (J), mass in kilograms (kg), and velocity in meters per second (m/s).
The work (W) of this force is equal to the difference between the final value and the initial value of the kinetic energy of the particle:


In this case:
- W=?
- m= 2,145 kg
- v2= 12

- v1= 25

Replacing:

W= -515,872.5 J
<u><em>The work required is -515,872.5 J</em></u>
Let the key is free falling, therefore from equation of motion
.
Take initial velocity, u=0, so
.

As velocity moves with constant velocity of 3.5 m/s, therefore we can use formula

From above substituting t,
.
Now substituting all the given values and g = 9.8 m/s^2, we get
.
Thus, the distance the boat was from the point of impact when the key was released is 10.60 m.
In this question all required information's are already provided. Based on these details the answer to the question can be easily determined. Let us now write down all the information's that are already given.
Mass of the roller coaster = 1000 kg
Velocity of the roller coaster = 20.0 m/s
We know the formula for finding the kinetic energy is
Kinetic energy = 0.5 * mass * (velocity) ^2
= 0.5 * 1000 * (20)^2
= 0.5 * 1000 * 400
= 200000 Joules
So the Kinetic energy of the roller coaster is 200000 joules.
i hope this helps you friend good luck on your quiz or lesson
Answer:
<h2>18150 J</h2>
Explanation:
The kinetic energy of the car can be found by using the formula

m is the Mass
v is the velocity
From the question we have

We have the final answer as
<h3>18150 J</h3>
Hope this helps you
Gravity lets all objects fall to the ground at the same speed, 9.8 m/s/s. If the force of gravity were stronger, such as 10 m/s/s, the rate of acceleration would be faster.