# PHYSICS QUESTION HELP?

I honestly have no idea how to go about this question. Please help!

An automobile having a mass of 650 kg is

driven into a brick wall in a safety test. The

bumper behaves like a spring of constant

7.47 × 106 N/m and compresses 2.7 cm as

the car is brought to rest.

What was the speed of the car before impact,

assuming no energy was lost during impact

with the wall?

Answer in units of m/s

### 1 Answer

Relevance

- JimLv 74 years agoFavorite Answer
SPE = 1/2kx² = (0.5)(7.47E6)(0.027)² = 2723 J

KE of car = SPE

1/2mV² = 2723

V² = 5446/650 = 8.3785

V = 2.89 m/s ANS

Still have questions? Get your answers by asking now.