Momentum
Momentum = mass x velocity kgms-1
= kg x m/s
1. A bowling ball has a mass
of 10kg and a velocity of 15m/s. Calculate its momentum. 150 kgm/s
2. A
speed skater has a velocity of 15m/s and a mass of 65 kg. Calculate her
momentum. 975 kgm/s
3. A bullet of mass 0.068 kg
traveling horizontally at a speed of 150 m/s. Calculate its momentum. 10.2 kgm/s
4.
The world record for bowling at
cricket is 80 m/s. A cricket ball has a mass of 0.17kg. Calculate its momentum.
13.6 kgm/s
5.
A jumbo jet has a mass of 30 000
kg. Calculate its momentum at cruising speed of 300ms-1
9 x 10 6
kgm/s
6.
The Earth has a mass of 5.9742 ×
1024 kg. Its orbital velocity is 29.8 km/s. Calculate its momentum. 1.73 x1029
kgm/s Jupiter has a mass of 1.8986×1027 kg and an orbital
velocity of 13.06 km/s. Calculate its momentum. 2.48 x1031
kgm/s
7.
N2 has an atomic mass
of 4.65173 x 10-26 kg.
Calculate its momentum if it has a velocity 500m/s 2.33 x 10-23 kgm/s
8.
A truck of mass 2kg travels at 8
m/s towards a stationary truck of mass 6kg. After the collision they stuck
together and move off in the same direction. What is their common velocity?
16kgm/s = (2+6 kg)v so 8v = 16 and v =2 m/s
9.
A car of mass 2000kg, traveling
at 10m/s, has a head on collision with a small sports car of mass 500kg. If
both cars stop dead on colliding, what was the velocity of the sports car
before the collision? Momentum after = 0 so (2000 x 10) + (500 x v) so 500v = 20000 and v = 40m/s
10.
A man wearing a bullet proof vest
stands on roller skates. His total mass is 80kg. A bullet of mass 20g is fired
at him at a speed of 400 m/s. If the bullet is stopped by the vest and falls to
the ground, what velocity will the man move at? Momentum
before = (0.02kg x 400) + 0 = 8kgm/s
Momentum after = 0 + (80kg x
v) = 8 kgm/s so 80v = 8 so v = 0.1m/s
after being hit
How does
your answer compare with “the movies”? They aren’t
real. (but then you knew that)
