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Find the average force needed to accelerates a car weighing 500 kg from rest to 72 km/h in a distance of 25 m.

Jayant Kumar , 11 Years ago
Grade 11
anser 2 Answers
Apoorva Arora

Last Activity: 10 Years ago

Here we use the third equation of motion. i.e.
2as=v^{2}-u^{2}
here s= 25 m
v= 72 km/hr = 20 m/s
u= 0
so
a= 8 m/s (square)
and hence the force is
F=ma= 4000 N

Klyen Dave

Last Activity: 7 Years ago

This question can be solved more easily using the “Work – Energy Theorem”
We know, Wnet ΔK.E
∴  ∑F x s = ½ mv- ½ mu2
∴ F x 24 = ½ x 500 x 202
∴ F = 4000N
 
 

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