1 -A body of mass 1 kg has weight 10 N at a certain place.

What is the weight of

a 100 g,

b 5 kg,

c 50 g?

2 -The force of gravity on the Moon is said to be one-sixth of

that on the Earth. What would a mass of 12 kg weigh

a on the Earth, and

b on the Moon?

3 -What is the force constant of a spring which is stretched

a 2 mm by a force of 4 N,

b 4 cm by a mass of 200 g?

4 – 3 a What resultant force produces an acceleration of 5 m/s2

in a car of mass 1000 kg?

b What acceleration is produced in a mass of 2 kg by a

resultant force of 30 N?

5- A block of mass 500 g is pulled from rest on a horizontal

frictionless bench by a steady force F and travels 8 m in 2 s.

Find

a the acceleration,

b the value of F.

6 -Starting from rest on a level road a girl can reach a speed of

5 m/s in 10 s on her bicycle. Find

a the acceleration,

b the average speed during the 10 s,

c the distance she travels in 10 s.

Eventually, even though she is still pedalling as fast as

she can, she stops accelerating and her speed reaches a

maximum value. Explain in terms of the forces acting why

this happens.

7 -What does an astronaut of mass 100 kg weigh

a on Earth where the gravitational fi eld strength is

10 N/kg,

b on the Moon where the gravitational fi eld strength is

1.6 N/kg?