Answer all of the following questions on a piece of loose leaf paper:
1) A runner whose weight is 800 N wishes to accelerate to 5 m/s2. What minimum coefficient of friction is required for her to accelerate without slipping?
2) A box decelerates as it moves to the right along a horizontal surface as shown in the diagram.
Draw a vector that best represents the force of friction on the box.
3) Sand is often placed on an icy road because the sand
a) decreases
the coefficient of friction between the car and the road
b) increases
the coefficient between the car and the road
c) increases
the normal force of the car on the road
d) decreases
the normal force of the car on the road
4) A different force is applied to four
1-kg blocks to slide them across a uniform level surface at constant speed, 2N, 3N, 4N & 5N. On which box is the
coefficient of friction the smallest? What is it?
5) Jill is pulling 200-N sled through the snow at a
constant speed with a constant horizontal force of 10-N. What is the
coefficient of friction between the sled and the snow? How much force would Jill have to apply in order to accelerate at a rate of 2 m/s/s?
