Question
The force shown in the force-time diagram in Figure P6.11 acts on a 1.4 kg object.
(a) Find the impulse of the force.
(b) Find the final velocity of the mass if it is initially at rest.
(c) Find the final velocity of the mass if it is initially moving along the x axis with a velocity of -1.7 m/s.
The diagram has an x axis of t(s) and a y axis of F(N)
It has the following coordinates:
(0,2) (3,2) (4,1) (5,0)
for (a) I tried finding the area of the triangle from x coordinates (3 to 5)with a height of 2. I thought I was supposed to do that, but I guess not.
(a) Find the impulse of the force.
(b) Find the final velocity of the mass if it is initially at rest.
(c) Find the final velocity of the mass if it is initially moving along the x axis with a velocity of -1.7 m/s.
The diagram has an x axis of t(s) and a y axis of F(N)
It has the following coordinates:
(0,2) (3,2) (4,1) (5,0)
for (a) I tried finding the area of the triangle from x coordinates (3 to 5)with a height of 2. I thought I was supposed to do that, but I guess not.
Answers
drwls
You did (a) correctly, if you got the area right.
For (b), divide the impulse (which equals the final momentum) by the mass. This assumes that it started out with zero velocity.
(c) In this case, the CHANGE in momentum equals the impulse from the graph
For (b), divide the impulse (which equals the final momentum) by the mass. This assumes that it started out with zero velocity.
(c) In this case, the CHANGE in momentum equals the impulse from the graph