Momentum Part 2

Momentum Part 2

Multiple Choice

Which expression gives the momentum of an object?

• mass × acceleration

• mass × gravitational field strength

• mass × velocity

• 1/2 × mass × (velocity)2

Multiple Choice

An object of mass 4.0 kg is moving with a velocity of 3.0 m / s in a straight line.

What is the momentum of the object?

• 0.75 kg m/s

• 1.3 kg m/s

• 12 kg m/s

• 24 kg m/s

Multiple Choice

A constant force acts on a body causing the momentum of the body to increase.

Which expression relates the force to the momentum and the time taken?

• 
  $force=\frac{change\ in\ momentum}{time\ taken}$
  

• $force=\frac{momentum}{time\ taken}$

• force = change in momentum x time taken

• force = momentum x time taken

ELASTIC COLLISION

SAME DIRECTIONS

OPPOSITE DIRECTIONS

Multiple Choice

What is the velocity of car A immediately after the crash?

• 26.67 m/s

• 30.0 m/s

• 36.7 m/s

• 55.0 m/s

Identify the value of m1, m2,u1,u2,v1 and v2

**Remember, opposite direction, velocity will be negative!!!

Multiple Choice

What is the velocity of the second ball after the collision?

• -1.0 m/s

• 1.0 m/s

• -2 m/s

• 2 m/s

Inelastic Collisions

Multiple Choice

A car of mass 1000kg travelling at 8.0m/s collides with a lorry of mass 3000kg that is travelling at 2.0 m / s in the same direction.

After colliding, the two vehicles stick together.

What is their speed after the collision?

• 2.0 m/s

• 2.5 m/s

• 3.5 m/s

• 5.0 m/s

A car of mass 1000kg travelling at 8.0m/s collides with a lorry of mass 3000kg that is travelling at 2.0 m / s in the same direction.

After colliding, the two vehicles stick together.

What is their speed after the collision?

m1 = 1000 kg

u1 = 8 m/s

m2 = 3000 kg

u2 = 2.0 m/s

Since they stick together:

(m1u1 + m2u2) = (m1+m2) v

(1000 x 8) + (3000 x 2) = (1000 + 3000)v

8000 + 60000 = 4000v

Thus, v = 14000/4000 = 3.5 m/s

Multiple Choice

An object P of mass 80 g collides with another object Q of mass 40 g.

After the collision, P and Q stick together and then travel on together.

Before the collision, P is travelling at a speed of 6.0 m / s and Q is at rest.

What is the speed of P and Q after the collision?

• 2.0 m/s

• 3.0 m/s

• 4.0 m/s

• 6.0 m/s

Object P of mass 80 g collides with another object Q of mass 40 g.

After the collision, P and Q stick together and then travel on together. Before the collision, P is travelling at a speed of 6.0 m / s and Q is at rest. What is the speed of P and Q after the collision?

m1 = 80g= 0.08 kg

m2 = 40 g = 0.04 kg

u1 = 6.0 m/s

u2 = 0 m/s

v =?

Since they stick together,

m1u1 + m2u2 = (m1+m2)v

(0.08x6.0) + (0.04x0) =(0.08+0.04)v

0.48 + 0 = 0.12v

Thus, v = 0.48 / 0.12 = 4.0 m/s