A single cable supports an 875kn elevator car. find the tension in the in the cable car moves with

a) constant speed
b) an upward acceleration of 3.50ms-2
c) a downward acceleration of 3.50 ms-2

a) At constant speed the net force has only to balance the weight (ignoring friction) .. no accelerating force is required .. .. ►F = 875 N

b) The tension force supports the weight and provides an upward accelerating force.
F = 875N + (m x a)
F = 875 + (875/9.80 x 3.50) .. ►F= 1187.50 N

c) The net force provides a downward acceleration
Net force .. F = (mg↓ - T↑) = m x a
T = m(g - a) = 875/9.80 (9.80 - 3.50) .. .. ►F = 580.30 N