1. A 500.0-g bird has gathered a breakfast of 10 juicy worms for her young offspring. Each worm has a mass of 5.00 g and must be delivered to the waiting offspring 10.0 m up in the tree. Calculate the least amount of work mother bird will have to do to feed breakfast to her little birds.(4 marks)

2. A 200.0 N force moves a 120.0-kg crate on a frictionless surface from rest to a final speed of 9.6 m/s. What is the displacement of the crate at the time it reaches this speed? (4 marks)

3. A student pushes a 5 kg box from rest with a force of 50 N for a distance of 4 m. While the student is pushing the box, a 10 N force of friction is acting on the box. Find:(5marks)

a) The work done by the student.

b) The work done by friction. c) The increase in energy of the box. d) The speed of the box after 4 m.

50 N

Ff= 10 N

4 m