# Homework Help: Momentum impulse physics question, HELP !

1. Oct 27, 2013

### enchantress95

Momentum impulse physics question, HELP ASAP plz!

1. The problem statement, all variables and given/known data
A 4.0-kg block slides along a frictionless surface with a constant speed of 5.0 m/s as shown. Two seconds after it
begins sliding, a horizontal, time-dependent force is applied to the mass. The force is removed eight seconds later. The
graph shows how the force on the block varies with time.
• What is the magnitude of the total impulse of the force acting on the block?
• What, approximately, is the speed of the block at t = 10 seconds?

2. Relevant equations

p= mv
K.E= 1/2*m*v^2

3. The attempt at a solution
p= mv = 20kg*m/s
K.E= 1/2*m*v^2 = 50 J

I was solving this past paper and the answer is 42N but idk how to get tht :s any help wud be appreciated, thanks!

2. Oct 27, 2013

### Simon Bridge

Welcome to PF;
You are missing an equation - $p=\int F(t)\; dt$