EXERCISES FOR CONSTRUCTION OF KNOWLEDGE

A 0.5kg ball is about to roll off the edge of a 1.5m tall table. What is its current potential energy?

g = 9.8ms²

• 13,33 J.

• 7,35 J.

• 14,7 J.

• 3,72 J.

Two satellites in space, each with a mass of 2000 kg, are 1500 m apart from each other. What is the force of gravity between them? G = 6,67.10^-11

• 3,12.10^-1 N.

• 6,22.10^-8 N.

• 8,87.10^-10 N.

• 1,19.10^-10 N.

A 12kg box starts at rest and reaches a velocity of 3.45ms after traveling a distance 12m. What was the force on the box?

• 0,041 N.

• 0,496 N.

• 2,95 N.

• 5,95 N.

A rock is dropped in freefall from some initial height h. Which of the following describes its final velocity right before it hits the ground?

• A

• B

• C

• D

A man stands at the top of a 21m tall building. He holds a 3.2kg rock over the edge. What is the potential gravitational energy of the rock? g =9,8 m/s²

• 658,56 J.

• 67,2 J.

• 77,2 J.

• 698,92 J.

Michael pushes a box 9m across the floor. If the box moves with a constant velocity, what is the total work done?

• We need to know the force used to find the work.

• We need to know the time to find the work.

• 0 J.

• 9 J.

Ryan pushes a 14 kg filing cabinet 2.1m across the floor, doing 88.2 J of work. How much force is he applying to the cabinet?

• 3 N.

• 13,23 N.

• 42 N.

• 9,80 N.

A 3.23kg book falls off the top of a 3.01m bookshelf. What is its kinetic energy right before it hits the ground?

g = 9.8 m/s²

• 16,04 J.

• 31,76 J.

• 95,28 J.

• 3,57 J.

A 10kg ball moving at 13ms strikes a 20kg ball at rest. After the collision the 10kg ball is moving with a velocity of 7ms. What is the velocity of the second ball?

• 6 m/s.

• 3 m/s.

• 8 m/s.

• 12 m/s.

A ball is thrown vertically with an initial velocity of 3.3m/s. What is the maximum height it will reach?

g=9.8m/s²

• 0,17 m.

• 0,34 m.

• 0,67 m.

• 0,18 m.