# Physics: work

1. Nov 21, 2004

### scan

anyone physic experts know how to do this questions?

A force of 25 N parallel to a 35degrees inclined plane pulls a 2.5 kg block 5 m up the plane at
constant speed.
(a) How much work has been done by the 25 N force?
(b) much work has been done by friction?
(c) How much work has been done by the gravitational force?

2. Nov 21, 2004

### Parth Dave

What have you done to try and solve the question? Where specifically are you have problems?

3. Nov 21, 2004

### WCU

work=F(average)*(cos theta)*distance
friction=coefficient of friction * Normal force
gravity is always 9.80m/s^2 on earth

4. Nov 21, 2004

### scan

this is what i got so far. W = F * distance

so by the diagram I got:

W = 25 N * 5m * cos 35

but i know thats wrong... i dont' know how i incorporate teh mass

5. Nov 21, 2004

### WCU

multiply the mass by gravity, but remember that gravity will be straight down and the normal force is perpendicular to the block, so use a net force diagram to sort out the remaining forces ... hope that helps, makes more sense in my head than it does typed, lol

6. Nov 21, 2004

### scan

what part of the question are you refering to?

7. Nov 21, 2004

### scan

for part a i got 102.4 J. does that look right?