The engines of a 1.20 x 10^5 N rocket exert an upward thrust of 2.00 x 10^5 N for 1.50 minutes upon lift off.

What is the impulse exerted on the rocket?

What is the velocity of the rocket at the end of the 1.50 minute period?

physics - bobpursley, Thursday, February 3, 2011 at 8:18pm
impulsr=force*time=2E5*90 N-seconds

changevelocity=impulse/massrocket

physics - help, Thursday, February 3, 2011 at 9:09pm
I don't understand where the 90 comes from

1.5 minutes is 90 seconds, last time I checked.

The 90 comes from converting 1.50 minutes into seconds. There are 60 seconds in a minute, so 1.50 minutes is equal to 1.50 x 60 = 90 seconds.

To find the impulse exerted on the rocket, you can use the formula impulse = force * time. In this case, the force exerted by the engines of the rocket is 2.00 x 10^5 N, and the time for which this force is exerted is 1.50 minutes. However, you need to convert the time from minutes to seconds in order to use the correct units in the formula.

To convert minutes to seconds, you multiply the number of minutes by 60 (since there are 60 seconds in one minute). So, 1.50 minutes is equal to 1.50 * 60 = 90 seconds. Therefore, the time in the formula is 90 seconds.

Now, you can calculate the impulse by multiplying the force and the time:

Impulse = (2.00 x 10^5 N) * (90 s)

Simplifying this expression will give you the value of the impulse exerted on the rocket.

Regarding the second part of the question, to find the velocity of the rocket at the end of the 1.50 minute period, you need to use the formula:

change in velocity = impulse / mass of the rocket

You already know the impulse from the previous part of the question, and the mass of the rocket is not given. So, to find the velocity, you need to know the mass of the rocket.