The speed of a cart changes from 12m/s to 34m/s in just 5 seconds.
What is the mass of the cart if the force the magnitude of the force acting on it is 6.3 newtons?

Step 1 Calculate the acceleration.
acceleration = change in speed/period of time
Change in speed = final speed - initial speed = 34 -12=22m/s
Period of time = 5 seconds
Acceleration = 22m/s/5/s = 4.4m/s/s

Step 2 The mass = 6.3/ 4.4 = 1.43 Kg

Incorrect

The formula you should use is
m=f/a