dynamics cart question

Question

A dynamics cart is pulled from rest by a net force of 1.2 N [forward]. The cart moves 6.6 m, reaching a velocity of 3.2 m/s [forward]. Determine the mass of the cart.

Answer 1

Assuming the acceleration is constant, use the kinematics equation:

v_f² = v_i² + 2ax where vf is the final velocity (3.2 m/s), vi is the intital velocity (0 m/s since it starts at rest), "a" is the acceleration, and "x" is the distance traveled (6.6 m):

3.2² = 0² + 2a(6.6)

10.24 = 13.2a

a = 0.7758 m/s²

Then use F = ma:

1.2 = m•0.7758

m = 1.2/0.7758 = 1.5 kg