Physics Dynamics

Question

What is the normal force supporting a 900 kg car in a mechanic’s garage on a lift when the lift is accelerating the car up at an acceleration of 1.6 m/s2?

Answer 1

Set the difference of the upward normal force and downward weight equal to mass*acceleration, per Newton's second law.

 

F_n = upward normal force (assume up is positive direction)

W = weight = mg

m = 900 kg

a = 1.6 m/s²

 

Newton's second law:

 

F = ma

 

F = F_n - W = F_n - mg

 

F_n - mg = ma

 

F_n = ma + mg = m(a + g)

 

Can you take it from here?