Phys 100: Problem Set Week 7

Reading:

We finish Giancoli Chapter 6 (work and energy) and will start on Chapter 7 (momentum) at the end of the next week, after break.

Problems: These are due Wednesday, October 17 at the beginning of class

(1) The vectors A, B and C are

A: magnitude 10.0 at 30.0 degrees counterclockwise from the x axis,

B: magnitude 4.0 at 10.0 degrees counterclockwise from the y axis, and

C = 5.6 i - 3.1 j

Compute the dot products (a) A· B and (b) B · C.

(2) A 40.0 kg crate is pushed a distance 5.0 m along a level floor at a constant speedby a force that pushes downward at an angle of 30.0 degrees from the horizontal. The coefficient of kinetic friction between crate and floor is 0.25. (a) What is the work done on the crate by this force? (b) How much work is done on the crate by the frictional force? (c) How much work is done by gravity? The normal force?

(3) Ch 6 P 5

(4) Ch 6 P 7

(5) Ch 6 P 8

(6) Ch 6 P 19

(7) Ch 6 P 22

(8) Ch 6 P 42

(9) Ch 6 P 73

(10) Ch 6 Question 15

(11) A toy car rolls (without friction in its bearings) on a loop-the-loop track of radius R. What is the minimum height h at which the car can start from rest and still make it around the loop? See Fig. 6–39.