If a car's mass is 600 kg, and its speed is 10 m/s. And a scooter's mass is 80 kg, and the scooter's speed is 50 m/s.

Then which will require more force to stop it if the distance is the same?

Question

If a car's mass is 600 kg, and its speed is 10 m/s. And a scooter's mass is 80 kg, and the scooter's speed is 50 m/s. 

Then which will require more force to stop it if the distance is the same?

thesmartone · Answer

@Michele_Laino :)

thesmartone · Answer

I thought we used f = ma

And then

f = 600 x 10
f = 6,000

And

f = 80 x 50
f = 4,000

So it would take more force to stop the car.

Am I correct? :P

michele_laino · Answer

the object which requires more force is the object which has the highest kinetic energy

michele_laino · Answer

now the kinetic energy of the car is:
0.5 * 600*100=30,000 Joules
whereas kinetic energy of scooter is: 0.5*80*2500=100,000 Joules

michele_laino · Answer

so it is the scooter

michele_laino · Answer

oops.. formula for kinetic energy is:
$KE=1/2 \cdot m \cdot v^2$

thesmartone · Answer

oh thank you so much :D

thesmartone · Answer

@eta @waterineyes there is your answer :p