Question

Read the passage given below and answer the questions that follow:
The quantities and causes of motion were summed up and mathematically related by the English
scientist, Sir Isaac Newton, more than three centuries ago. These are now known as ‘Newton’s Laws of
Motion’. There are three laws of motion: Newton’s first law of motion gives rise to the idea of inertia.
Newton’s second law of motion derives a relationship between the cause (force) and quality
(acceleration). Newton’s third law of motion gives rise to the idea of cause and effect (action and
reaction). Newton’s laws of motion coupled with his insights into the nature of gravity, accounts for
every movement in the universe, large or small, from the vibration of the tiniest atom to the movements
of planets and stars.
a) State Newton’s second law of motion.
b) A moving truck takes a much longer time to stop than a moving car when brakes are applied to both
at the same time. Why?
c) Find acceleration of a body of mass 10 kg when it is subjected to a horizontal force of 100 N, if it is
moving along (i) a smooth horizontal surface, (ii) a horizontal surface which produces a frictional force
of 80 N.

Answer 1

1. Newton’s second law of motion derives a relationship between the cause (force) and quality
2. Because a truck will typically have more mass due to being larger and made with denser materials to increase strength, it has more momentum at thesame speed. This increased momentum requires more force to stop it and thus it can take a longer distance if a similar breaking force is applied
3. 10ms^-2

• 2ms^-2
• a=f/m