Answer:
6.76 s
Explanation:
Power = Energy/time
P = E/t ....................... Equation 1
Where P = Power, E = kinetic energy, t = time.
But,
E = 1/2m(Δv)²................... Equation 2
Where m = mass of the car, Δv = change in velocity.
Substitute equation 2 into equation 1
P = 1/2m(Δv)²/t................... Equation 3
Given: m = 1300 kg, Δv = 65-35 = 30 km/h = 30(1000/3600) m/s = 8.33 m/s, t = 3.8 s
Substitute into equation 3
P = 1/2(1300)(8.33²)/3.8
P = 11869.15 W.
Assuming the power stays the same,
making t the subject of formula in equation 3
t = 1/2m(Δv)²/P.................... Equation 4
Given: m = 1300 kg, Δv = 95-55 = 40 km/h = 11.11 m/s, P = 11869.15 W
Substitute into equation 4
t = 1/2(1300)(11.11²)/11869.15
t = 6.76 s
