Answer:
310 N
Explanation:
Draw a free body diagram of the clown. There are five forces:
Tension force T pulling up.
Normal force N pushing up.
Weight force W pulling down.
Tension force T pulling left.
Friction force Nμ pushing right.
Sum of the forces in the y direction:
∑F = ma
N + T − W = 0
N = W − T
Sum of the forces in the x direction:
∑F = ma
Nμ − T = 0
T = Nμ
Substitute and solve for T:
T = (W − T)μ
T = Wμ − Tμ
(1 + μ) T = Wμ
T = Wμ / (1 + μ)
Plug in values and solve:
T = (890 N) (0.53) / (1 + 0.53)
T ≈ 310 N
The clown must pull with at least 310 N to yank his feet out from under himself.
