Answer:
(A) time = 3.205 s
(B)time =4.04 s
Step-by-step explanation:
mass (m) = 850 kg
power (P) = 40 hp = 40 x 746 = 29,840 W
final velocity (Vf) = 15 m/s
final height (Hf) = 3 m
since the car is starting from rest at the bottom of the hill, its initial velocity and initial height are both 0
(A) from the work energy theorem
- work = 0.5 x m x (
) (change in kinetic energy) - work = power x time
- therefore
power x time = 0.5 x m x (
)
time =
)}{power}[/tex]
time =
)}{29,840}[/tex]
time = 3.205 s
(B) from the work energy theorem
- work = change in potential energy + change in kinetic energy
- work = (mg (Hf - Hi)) + (0.5m(
)
- work = power x time
- therefore
power x time = (mg (Hf - Hi)) + (0.5m(
)
time =
)}[/tex])}{power}[/tex]
time =
)}[/tex])}{29,840}[/tex]
time =4.04 s