# Just need help with GCSE Physics question

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#1
A family car has a mass of 1400kg. In an accident it hits a wall and goes from a speed of 27m/s to a standstill in 1.5 seconds. By how much would the force have been reduced if the car had had a crumple zone that increased the collision time to 2.2 seconds? Give your answer to the nearest whole number.

I know it may it seem simple, I'm confused though. Thanks for help (if any haha).
0
1 year ago
#2
The change in momentum is called the impulse. This is equal to force × time.
So you can calculate the change in momentum from what you've been given, and you're told the time taken for it to happen.
Remember that the total change in momentum is the same in both cases.

So, longer time means a lower force. Shorter time means a higher force.
Last edited by Sinnoh; 1 year ago
1
#3
Hi, thanks for the reply. Just another quick question:

The driver of a 1000 kg car is speeding. He loses control and collides with a wall, coming to a stop. The crumple zone of the car absorbed 90 kN of force in 0.5 seconds. What was the car's speed at the time of impact?

Thanks very much!
(Original post by Sinnoh)
The change in momentum is called the impulse. This is equal to force × time.
So you can calculate the change in momentum from what you've been given, and you're told the time taken for it to happen.
Remember that the total change in momentum is the same in both cases.

So, longer time means a lower force. Shorter time means a higher force.
0
1 year ago
#4
Just use:
"The change in momentum is called the impulse. This is equal to force × time."
0
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