Find the acceleration of the deer during collision.

Question

A 1200kg car collides with a 160kg deer. The collision results in an acceleration ("deceleration") of 2.5m/(sec)^2 for the car. Find the acceleration of the deer during the collision. Find the acceleration of the deer during collision.

Answer 1

By Newton's 3rd law, the 2 forces in this problem must be equal and opposite. Calculate the force on the car using Newton's 2nd law, set it equal to the force on the dear but with opposite sign, and then use Newton's 2nd law to find the acceleration of the deer.

m₁ = mass of car = 1200 kg

a₁ = acceleration of car = -2.5 m/s² (negative since it is a deceleration)

m₂ = mass of deer = 160 kg

a₂ = acceleration of dear = ?

You know F = ma (2nd law) and the forces are equal and opposite (3rd law), so

m₁a₁ = -m₂a₂ ⇒

a₂ = -m₁a₁ / m₂

Plug in the numbers and finish from here. Be careful with signs. The answer will be in m/s².