key advice

Question 1

ALWAYS SHOW EVERY FORMULA AND STEP OF YOUR WORK

Answer 1

on god

Question 1

If a motorized cart is pulling up a block using a pulley, which one has more net force?

1. whichever has more inertia
2. the block, gravity is not balanced by a normal force
3. the motorized cart, it needs to lift the block
4. neither, both are part of the same system

Answer 1

1. whichever has more inertia, as f = ma, and both are accelerating at the same rate thus force is dependent on mass

Question 2

using F = ma, which object in a system of pulled blocks by string has the greatest net force? VERY IMPORTANT CONCEPT

Answer 2

the one which has the greatest mass, the accelerations are all the same

Question 3

You have a graph of force vs. time from 0-6 seconds. if the 0-2 s interval has an average (increasing) force of 5 N, 2-4 s has a constant force of 10 N, and 4-6 s has an increasing average force of 15 N.

there is no resistive forces.

which is a correct statement about the motion:

A. the speed of the object is constant between 2 s and 4 s
B. the speed of the object is increasing during the entire 6 s interval
C. the object begins moving at roughly 2 s (there is no force at the origin)
D. the avg acceleration of the object during the 0-2 s is the same as the avg acceleration during the 4-6 s

Answer 3

B, as the force is increasing the whole time but the average acceleration is not (5 N at 0-2, 15 at 4-6 s)

Question 4

F = pi r^2 graph

Answer 4

exponential increase, r increases by one but f increases by the square of r

Question 5

when is kinetic energy conserved?

Answer 5

if non-conservative forces do no work and there are no external forces (but in the cases of potential energy transfer to kinetic like down a ramp, the external force of gravity is accounted for and it works)

basically when only internal nonconservative forces are acting