Elastic and Inelastic Collisions

The law of conservation of momentum states that, 

• p before is less than p after
• p before is the same as p after
• p before is more than p after

Tags

NGSS.HS-PS2-2

A 2.5 kg ball moving at 4.2 m/s collides with a 2.5 kg stationary ball. If the first ball is at rest after the collision, what is the velocity of the second ball? 

• 2.1 m/s
• 2.5 m/s
• 4.2 m/s
• 8.4 m/s

Tags

NGSS.HS-PS2-2

Collisions can be ____________or ___________.

• fast or slow
• far or near
• elastic or inelastic
• none of the above

Tags

NGSS.HS-PS2-3

When is momentum conserved in a collision?

• When the collision is inelastic.
• When the collision is elastic.
• When the collision is inelastic OR elastic but never an explosion.
• All collisions.

Tags

NGSS.HS-PS2-2

While playing pool, Emma notices that the pool balls bounce apart.  What type of collision is this?

• Elastic
• Inelastic
• Explosive
• Force

Tags

NGSS.HS-PS2-2

A billiard 𝑏𝑎𝑙𝑙 1 moving to the right with a speed 𝑣 collides with another identical billiard 𝑏𝑎𝑙𝑙 2 at rest. After collision, 𝑏𝑎𝑙𝑙 1 comes to rest.What is the velocity of 𝑏𝑎𝑙𝑙 2 after collision?

• 1v

• 2v

• -0.5v

• 0.5 v

A 0.2𝑘𝑔 bullet moves at a constant speed of 400𝑚/𝑠 and collides with a stationary 10𝑘𝑔 wooden block resting on a frictionless surface. What is the velocity with which the bullet and the block move off together after collision?

• 8.0 m/s

• 7.84 m/s

• 80.0 m/s

• 200 m/s

Before an elastic collision, the total kinetic energy of two objects was 200 𝐽. If the kinetic energy after

the collision of the objects became 80 𝐽, how much is the kinetic energy of the other object?

• 120J

• 200 J

• 0 J

• 280 J

A ball of clay has a kinetic energy of 16 J and was thrown to hit a stationary billiard ball. How much is the total kinetic energy of the two balls after the collision?

• 0 J

• More than 16J

• Less than 16J

• Less than 0J

In elastic collisions

• KE and linear momentum are conserved

• Only KE is conserved

• Only linear momentum is conserved

• neither KE nor momentum are conserved