Answer:
65.3 N
Explanation:
Draw a free body diagram. There are 3 forces on the wheel:
Weight force mg at the wheel's center pulling down,
Reaction force R at the edge of the step pushing towards the wheel's center,
Applied force F at the wheel's center pushing right.
We will need to sum of torques about the edge of the step. First, we need to find the horizontal and vertical distances between the wheel's center and the edge of the step.
y = 30 − 12 = 18 cm
x = √(30² − 18²) = 24 cm
Summing the torques about the edge of the step:
∑τ = Iα
mg x − F y = 0
F = mg x / y
F = (5 kg) (9.8 m/s²) (24 cm) / (18 cm)
F = 65.3 N
