Ablock weighing 15 newtons is pulled to the top of an incline that is 0.20 meter above the ground, as shown below. if 4.0 joules of work are needed to pull the block the full length of the incline, how much work is done against friction?

Total work done here against two forces

1. Work done against gravity

2. work done against friction

Here work done against gravity is given by

here we know that weight of the block will be

now we will say

as we know that total work

so work done against friction is 1 J

d is the correct answer

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.