Bob, who has a mass of 65 kg, can throw a 600 g rock with a speedof 35 m/s. The
ID: 1669257 • Letter: B
Question
Bob, who has a mass of 65 kg, can throw a 600 g rock with a speedof 35 m/s. The distance through which his hand moves as heaccelerates the rock forward from rest until he releases it is 1.0m. a. Whatconstant force must Bob exert on the rock to throw it with thisspeed? b. If Bob isstanding on frictionless ice, what is his recoil speed afterreleasing the rock? a. Whatconstant force must Bob exert on the rock to throw it with thisspeed? b. If Bob isstanding on frictionless ice, what is his recoil speed afterreleasing the rock?Explanation / Answer
Mass of bob m = 65 kg
Mass of rock M = 600 g = 0.6 kg
Initial speed u = 0
Distance S= 1 m
Final speed v = 35 m/ s
From the relation v ^ 2-u ^ 2= 2aS
Acclertion a = [ v ^ 2- u ^ 2] / 2S
= 612.5 m / s ^ 2
Force must bob exert on the rock F = ma
= 367.5 N
(b). recoil speed V = Mv / m
= 0.323 m / s