What is the kinectic energy of an object that has a mass of 30 kilograms and moves with a velocity of 20 m/s?

Question

A. 2,940 J
B. 5,880 J
C. 6,000 J
D.12,000 J


A car with a mass of 1,200 kilograms is moving around a circular curve at a uniform velocity of 20 meters per second. The centripetal force of the car is 6,000 newtons. What is the radius of the curve?

A.160 meters
B.80 meters
C.32 meters
D.16 meters

Answer 1

1. C
KE=.5*m*v^2
.5*30*20^2=6000 J

2. B
The force is
m*w^2*r and
w*r=v
so
m*v^2/r

6000=1200*20^2/r
r=1200*400/6000
r=80 m

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