Question

?

Answer 1

100 N to the left
175 N to the right

what is the net force?

Answer 2

A

Answer 3

✓

Answer 4

so it only wants the x-direction so there are only two relevant forces - the pedalling force + the air resistance

400N pedalling to the right
300N resisting air force to the left

what's the net?

Answer 5

A

Answer 6

good

Answer 7

knowing that this would be C?

Answer 8

force of gravity = mg

force of gravity - air resistance = ?

Answer 9

B

Answer 10

good

Answer 11

do you know how you would sketch the Free body diagram for this situation?

Answer 12

it would definitely be a slope

Answer 13

have to be careful here - it doesn't say the sled is on a slope, the sled is not on an angle but the force is

Answer 14

oh okay so I'm wrong then here right

Answer 15

then the angled force (25 deg 30N)

Answer 16

now, if you remember our decomposition formulas:

horizontal force = force * cos(theta)
vertical force = force * sin(theta)

Answer 17

in the y-direction we have:

Fsin(theta) pointing up
Fnormal pointing up
Fg pointing down

so Fsin(theta) + normal force - weight force = 0 (since no movement in the y-direction)

you can plug F , theta, and gravity into the equation to solve for the normal force

Answer 18

F is the applied force (30N)
theta is the angle (25 degrees)
Fg = mg

Answer 19

C

Answer 20

good

Answer 21

D?

Answer 22

similar formula (y-component --> vertical component --> Tension* sin(theta))

Answer 23

good, d

Answer 24

A?

Answer 25

the man is not moving in the y-direction so normal force and gravity cancel out

normal force = gravity force = ?

Answer 26

good, A

Answer 27

Have no idea on this one

Answer 28

N = mgcos(theta), choice C (to derive this you have to use a bit of trigonometry, can explain some other time)

Answer 29

C?

Answer 30

good