A box of mass 8.0 kg rests on a horizontal rough surface. A string attached to the box passes over a smooth pulley and supports a 2.0 kg mass at its other end.
When the box is released, a frictional force of 6.0 N acts on it.
What is the acceleration of the box?
A 1.4 m s^–2
B 1.7 m s^–2
C 2.0 m s^–2
2.6 m s^–2
What is the definition of the force on a body?
A the mass of the body multiplied by its acceleration.
B the power input to the body divided by its velocity.
C the rate of change of momentum of the body.
D the work done on the body divided by its displacement .
Newton’s third law of motion is often summarised as ‘Every action (force) has an equal and opposite reaction.’
A book rests on a table.
If the weight of the book is the ‘action’ force, what is the ‘reaction’ force?
A the pull of the book on the Earth
B the pull of the Earth on the book
C the push of the book on the table
D the push of the table on the book
A 0.10 kg mass is taken to Mars and then weighed on a spring balance and on a lever balance.
The acceleration due to gravity on Mars is 38% of its value on Earth.
What are the readings on the two balances on Mars? (Assume that on Earth g = 10 m s^–2.)
Water is pumped through a hose-pipe at a rate of 90 kg per minute. It emerges from the hose-pipe horizontally with a speed of 20 m s^–1.
Which force is required from a person holding the hose-pipe to prevent it moving backwards?
A 30 N
B 270 N
C 1800 N
D 10 800 N
A man weighs 240 N on Mars where the acceleration of free fall g is 4 m.s^–2. On the Moon, g is 2.0 m.s^-2.
Which statement is correct?