Acceleration of a Cart Pulled by Different Forces

[runningirl]

please help :) force question

Homework Statement

Use g=10 N/kg for this problem.
A 0.50 kg cart is on a level track. A horizontal string is pulling the cart. The string goes over a pulley and there is a 0.25 kg mass hanging at the other end.

a) What is the acceleration of the cart, if there is no friction>

b) Would the acceleration be different if there were a student pulling the string with a force of 2.5 N, rather than the 0.25 kg mass doing the pulling?

Homework Equations

T+(-mg)=ma

The Attempt at a Solution

for part B, i said it wouldn't matter because ultimately, 2.5 N=0.25 kg in this case because 2.5= 10*(m).

 

[venkatg]

The 0.25 kg mass hanging from the string pulley creates a tension T = m*g

T = 0.25 * 10 = 2.5N

The tension is the same all the way to the cart. As per the problem the cart has no friction.
So the cart weighing 0.5 kg is being moved by a force T = 2.5N

Acceleration is 2.5N/0.5 = 5m/sec^2

If a student pulled instead of the 0.25 kg mass, it would generate 2.5N force and the acceleration would be same.