Some physics sums....

[spiderman]

Hey guys
pls cud ull solve these sums.....


1) It takes 80N to compress the spring of a toy pop gun 0.200m to "load" a 0.18kg ball. With what speed will the ball leave the gun?

2)A football is kicked at ground level with a speed of 18m/s at an angle of 35 degrees to the horizontal.How much later does it hit the ground?

3)A ball thrown horizontally at 22m/s from the roof of a building lands 36m from the base of the building. How tall is the building?

4)An elevator (mass 4850 kg) is to designed so that the maximum acceleration is 0.0680g. What are the maximum and minimum forces the motor should exert on the supporting cable?

5)A 75 kg thief wants to escape from a third story jail window. Unfortunately, a makeshift rope  made of sheets tied together can support a mass of only 58kg.How might the thief use this rope to escape? Give a quantative answer.........

Please helppppp!!!

[nid404]

I'm not sure abt the first one.....

I will answer the others after a while....the second one goes here

Refer to the diagram

change in vertical motion would be

2X (18sin35)=20.65m/s
time it is in the air= 20.65/g
v=at
therefore t=v/a(g)
therefore time= 20.65/9.81=2.1s

You should be able to do the third one with the help of this actually but if you don't get it i can post that too

[nid404]

Okay the fourth one seemes a little weird but I assume they are asking for the maximum or minimum force to be applied are when there are no people on it....cuz otherwise it's a very vague question

The maximum force required would be when the lift is moving up with maximum acceleration

Force-48500=4850X0.068
F=48829.88N

The minimum force to be applied on the cable would be when the elevator is decelerating at -0.068./s2

This wouldbe F-48500=4850X-0.068
F=48170.2N

I assume it is done this way but I'm still not sure whether the question wants this