The Equations of
Motion 1
T.H.
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Q. 1
A car is moving at a velocity of 25 m s–1. It
accelerates at a rate of 6 m s–2. Find its
velocity after 3 seconds.
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Ans. 1
A car is moving at a velocity of 25 m s–1.
It accelerates at a rate of 6 m s–2.
Find its velocity after 3 seconds.
ANSWER
u
v a
25 ? 6
s
t
3
Use the no s equation:
v  u  at
 25  6  3  43 m s1
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Q. 2
An object is dropped from rest. Calculate its
velocity after 2.5 seconds if it is dropped:
(a) on earth, where the acceleration due to
gravity is 9.8 m s–2
(b) on mars, where the acceleration due to
gravity is 3.8 m s–2?
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Ans. 2
Note: when an object is dropped from rest,
its initial velocity is 0.
(a)
u v
a
s
0 ? 9.8
t
2.5
v  u  at  0  9.8  2.5  24.5 m s 1
(b)
u v
a
0 ? 3.8
s
t
2.5
v  u  at  0  3.8  2.5  9.5 m s 1
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Q. 3
A motorbike is travelling with a velocity of 3 m s–1.
It accelerates at a rate of 9.3 m s–2 for 1.8 seconds.
Calculate the distance it travels in this time.
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Ans. 3
A motorbike is travelling with a velocity of 3 m s–1.
It accelerates at a rate of 9.3 m s–2 for 1.8 seconds.
Calculate the distance it travels in this time.
ANSWER
u v
3
a
s
t
9.3 ? 1.8
1 2
s  ut  at
2
1
 3 1.8   9.3 1.82  20.47 m
2
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Q. 4
A Tesla Roadster car accelerates from rest at a
rate of 7.1 m s–2 for a time of 3.9 s.
Calculate the distance it travels in this time.
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Ans. 4
A Tesla Roadster car accelerates from rest at a
rate of 7.1 m s–2 for a time of 3.9 s.
Calculate the distance it travels in this time.
ANSWER
u v
0
a
s
t
7.1 ? 3.9
1 2
1
2
s  ut  at  0  3.9   7.1 3.9  54.0 m
2
2
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Q. 5
A bullet accelerates at a rate of 90 000 m s–2
from rest.
Calculate its velocity if it travels a distance of 0.5 m
while accelerating.
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Ans. 5
A bullet accelerates at a rate of 90 000 m s–2 from rest.
Calculate its velocity if it travels a distance of 0.5 m while
accelerating.
ANSWER
u v
a
s t
0 ? 90000 0.4
v 2  u 2  2as  02  2  90000  0.5  90000
v  90000  300 m s 1
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Q. 6
An aircraft is travelling along a runway at a
velocity of 25 m s–1.
It accelerates at a rate of 4 m s–2 for a distance
of 750 m before taking off.
Calculate its take-off speed.
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Ans. 6
An aircraft is travelling along a runway at a velocity of 25 m s–1.
It accelerates at a rate of 4 m s–2 for a distance of 750 m before
taking off. Calculate its take-off speed.
ANSWER
u v a
s
t
25 ? 4 750
v  u  2as  25  2  4  750  6625
2
2
2
v  6625  81.4 m s
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Q. 7
A car is travelling at a speed of 21 m s–1.
It accelerates at an average rate of 3 m s–2
for a time of 4 seconds.
Find the distance it travels during the 4 seconds.
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Ans. 7
A car is travelling at a speed of 21 m s–1.
It accelerates at an average rate of 3 m s–2
for a time of 4 seconds.
Find the distance it travels during the 4 seconds.
ANSWER
u
21
v a s
t
3 ? 4
1 2
1
s  ut  at  21 4   3  4 2  108 m
2
2
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