U4 Review

Rearranging Equations

100

Starting with the momentum equation, p = mv, solve for v.

v = p / m

200

Starting with the impulse equation, mΔv = FΔt, solve for Δt

Δt = mΔv / F

300

Starting with the explosion equation, m₁v₁ = - m₂v₂, solve for m₂ 

m₂ = - m₁v₁ / v₂

400

If rearranging the impulse equation for force gives the equation: F = mΔv / Δt, what happens to the Force when I increase the Δv? What happens to the force when I increase Δt?

Increase Δv ⇒ increases F

Increase Δt ⇒ decreases F

500

Starting with the elastic collisions equation, m_1iv_1i + m_2iv_2i =  m_1fv_1f + m_2fv_2f, solve for v_2f.

v_2f = (m_1iv_1i + m_2iv_2i - m_1fv_1f) / m₂

Identifying Type of Collision / Explosion

100

Two hockey pucks collide and stick together, moving as one afterward. What type of collision / explosion?

Inelastic collision

200

A firework explodes midair into two equal pieces that fly in opposite directions. What type of collision / explosion?

Explosion

300

Two billiard balls collide and bounce apart with no kinetic energy lost. What type of collision / explosion?

Elastic Collision

400

A cannon fires a cannonball. If I know the momentum of the cannon after it shoots, which equation would allow me to solve for the momentum of the cannonball?

Explosion

m₁v₁ = - m₂v₂

500

Caleb’s car gets rear-ended by Olivia. The cars stick together afterward. Which equation would help me solve for the final velocity, rearranged for final velocity?

Inelastic Collision

m_1iv_1i + m_2iv_2i =  (m₁ + m₂)v_f

v_f = (m_1iv_1i + m_2iv_2i) / (m₁ + m₂)

Calculating

100

A 0.5kg ball changes velocity from 2m/s to 10m/s. Find impulse.

4 Ns

200

A 4kg object explodes at rest into two 2kg pieces. One moves at 6m/s right. What is the velocity of the other?

-6 m/s

300

A 1000kg car at 10m/s hits a 1500kg car at rest. They stick. Find final velocity.

4 m/s

400

A 1kg ball at 5m/s hits a 1kg ball at rest in a perfectly elastic collision. What happens?

They swap velocities.

First stops, second moves at 5m/s.

500

A 1200kg car slows from 20m/s to 0 in 5s. What is the average force?

-4800N

Calculating Pt2

100

What are the units for:

~Force

~Kinetic Energy

~Momentum

~Impulse

~Force ⇒ Newtons

~Kinetic Energy ⇒ Joules

~Momentum ⇒ Ns or kg*m/s

~Impulse ⇒ Ns or kg*m/s

200

A 2kg cart moving at 4m/s hits a 3kg cart at rest. They stick together. What is their final velocity?

1.6 m/s

300

A 3kg object explodes into a 1kg piece moving at 8m/s right. Find the velocity of the 2kg piece.

-4 m/s

400

If momentum is conserved but kinetic energy decreases, what type of collision occurred?

Inelastic Collision

500

A 1kg cart going at 6m/s elastically collides with a 3kg cart, which is initially at rest. The final velocity of the 3kg cart is 3m/s forward. What is the final velocity of the 1kg cart?

-3m/s

Random

100

Which president is presidents’ day for?

Washington

200

The Lunar New Year is February 17, 2026. It’s the year of which animal?

Horse

300

What is the color of the money envelopes given out during Chinese New Year?

Red

400

Which number is lucky in Chinese culture?

8 (八, bā) is the luckiest due to its resemblance to "fā" (发), meaning wealth and prosperity

500

What are the five animals in the Furious Five in Kung Fu Panda franchise?

Tiger (Tigress), Monkey, Mantis, Crane, Snake (Viper)