1. Which of the following diagrams show balanced forces?

2. A fully loaded oil super-tanker moves at a constant speed of 12 ms^-1. It’s engines produce a constant forward force of 16 000 N. What is the size of the friction force acting on the tanker?

3. A clock hangs from a peg on a wall. If the weight of the clock is 2 N what is the size of the upward force provided by the peg?

4. David cycles along the road at a constant speed of 8 ms^-1. The total friction force acting on David and the bike is 550 N.

 

What size is the forward force provided by David pedalling?

5.    A crane holds a concrete slab of mass 750 kg at a steady height while workmen prepare to position it on the building they are constructing.

       (a)             What is the weight of the concrete slab?
       (b)             What is the tension in the crane cable?

6.         A helicopter is hovering at a constant height of 35 m. The upward lift force on the helicopter is 85 500 N.

(a) What is the weight of the helicopter?
(b) What is the mass of the helicopter?