An auto race is held on a circular track. A car completes one lap in a time of 24.6 s, with an average tangential speed of 38.0 m/s. Find (a) the average angular speed and (b) the radius of the track.

(a) 0.255 rad/s.

(b) 149.02 m

Explanation:

(a)

The expression for the average angular speed of the car is given as,

ω = 2π/T Equation 1

Where ω = Angular speed, T = period of the car, π = pie.

Given: T = 24.6 s,

Constant: π = 3.14

Substitute into equation 1

ω = 2(3.14)/24.6

ω = 0.255 rad/s.

(b)

The expression for tangential speed, angular speed and radius s given as

s = rω equation 2

Where s = tangential speed, r = radius of the track, ω = angular speed.

make r the subject of the equation

r = s/ω Equation 3

Given: s = 38 m/s, ω = 0.255 rad/s

Substitute into equation 3

r = 38/0.255

r = 149.02 m.

Hence the radius of the track = 149.02 m

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

hello there!

your answer is a “generator”

a generator does not create energy but instead it transforms it.

it’s basically a motor working in reverse.