Newton's laws test with answers for grade 8 science (free PDF download)

Quick answer: Newton's first law says an object keeps its motion unless an unbalanced force acts on it. This grade 8 science test on newton's laws has 8 questions worth 20 marks, to do in 40 minutes: first law and inertia, crate on a floor and cricket ball. The mark scheme is on a separate page; free printable PDF.

Also, this test has eight questions on inertia, F = m × a and action-reaction pairs and is worth 20 marks. Then, show every step of any calculation and give units. use g = 9.8 N/kg where it is needed.

Level: Grade 8 science (Year 9 · Class 8) · Curriculum: MS-PS2-1, MS-PS2-2

Time: 40 minutes · 8 questions · Total: 20 marks · Calculator allowed

Contents

Question 1 First law and inertia (2 marks)

Also, state Newton’s first law. (1 mark)
Afterwards, state what is meant by inertia. (1 mark)

Question 2 Crate on a floor (3 marks)

A crate of mass 12 kg is pushed across a floor. Moreover, the forces on it are shown.

Forces on a crate.

In addition, calculate the net force on the crate. (1 mark)
Also, calculate the acceleration of the crate. (2 marks)

Question 3 Cricket ball (3 marks)

A cricket ball of mass 0.15 kg is hit and accelerates at 400 m/s².

Then, calculate the average force of the bat. (2 marks)
A ball of mass 0.30 kg is hit with the same force. State its acceleration. (1 mark)

Question 4 Rocket (3 marks)

In addition, state Newton’s third law. (1 mark)
A rocket pushes gas downward out of its engine. Afterwards, name the reaction force. (1 mark)
Moreover, explain why the rocket accelerates upward. (1 mark)