Mechanical Energy

What is the definition of work in physics?

• The amount of energy required to move an object

• The distance an object moves in a given time

• The product of the force applied to an object and the distance it moves in the direction of the force

• The amount of force required to move an object

A crane lifts a 100 kg weight to a height of 10 meters. How much work is done on the weight?

• 100 J

• 1000 J

• 10.000 J

• 100.000 J

The total mechanical energy of a system is conserved when ...

• The system is at rest

• The system is in motion

• There is no friction

• The system is undergoing a collision

Which of the following factors affects the potential energy of an object?

• Mass of the object

• Height of the object

• Velocity of the object

• Temperature of the object

What is mechanical energy?

• Energy associated with motion

• Energy associated with position

• Both A and B

• None of the above

A roller coaster is an example of a system that has both kinetic and potential energy. Which of the following statements is true?

• The roller coaster only has kinetic energy at the top of a hill

• The roller coaster only has potential energy at the bottom of a hill

• The roller coaster has both kinetic and potential energy at any point on the track

• The roller coaster has no energy at the top of a hill

1 Kg ball is dropped from a height of 10 meters. What is its kinetic energy just before it hits the ground?

• 0 J

• 50 J

• 100 J

• 200 J

An object with a mass of 2 kg is thrown upwards with an initial speed of 30 m/s. What is the speed of the object when it is at a height of 25 meters?

• 10

• 15

• 20

• 30

A ball with a mass of 5 kg is dropped from the top of a building with a height of 90 m. what is the speed of the ball when it is half the height of the building?

• 50 m/s

• 40 m/s

• 30 m/s

• 20 m/s

An object is thrown up from the top of a building with a height of 100 m with a speed V, when the object reaches 60 meters below the top of the building its speed is 2V. What is the initial velocity of the object when it is thrown?

• 10 m/s

• 20 m/s

• 30 m/s

• 40 m/s