Question

The ground reaction force acting on Carter during his long jump is 4500 N acting forward and upward at an angle of 78 degrees from horizontal. Carters mass is 70 kg. Other than gravity, this is the only external force acting on Carter. a. What is the vertical component of this ground reaction force? b. What is the horizontal component of this ground reaction force? c. How big is the net force, the sum of all the external forces, acting on Carter?

Answer 1

a. 4500*sin78=4401 N
b. 4500*cos78 = 935 N
c. this one is from geometry.
Two forces 4500N and 686N with the angle 78+90=168 in btw of them
Net force =
`\sqrt{ 4500^(2) + 686^(2) - 2*4500*686*cos168 }` = 3831 N

Answer 2

I solved a. and b. by X component = 4500 N x sin (78) = 4402 Y component = 4500 N x cos(78) = 936 N I need help solving c. supposedly the answer is 3831 N