Question

A dog of mass 16kg slides down a playground slide. The slide is tilted at an angle of 52° with respect to the ground. The coefficient of kinetic friction between

the dog and the slide is μ=0.23. While the dog is sliding, an angry cat is pulling the dog down the slide with a force of 10 N, and a worried puppy is pulling the dog up

the slide with a force of 7 N!

a.What is the weight of the dog?

b.What is the normal force on the dog?

c.What is the force of friction on the dog?

d. What is the acceleration of the dog down the slide?

e.If the vertical height of the slide is 3 meters, how much work does gravity do on the dog?

Answer 1

Now, Work done by gravity

d is the displacement

Now,

where h is the vertical height = 3m

So, W = mgd x h/d = mgh = 16 x 9.8 x 3 J = 470.4 J (e)

Hence, the values are

a) 156.8 N

b) 96.54 N

c) 22.2042 N

d) 6.77 ms^-2

e) 470.4 J