Answer:
(d) Negative.
Explanation:
let's test each at a time.
(a) It can't be 0, because cup would slide back other wise.
(b) Positive, well if forward is positive, than the work done against the forward acceleration must be negative , so it can't be positive.
(c) Equal to non-conservative work done by the car's engine.
well no, because work done by car's engine dosen't go all of it into getting car to move, so it can't be that.
(d) negative, this look like it, because work that friction does must be nagative to counteract positive thrust of car which is positive and in forward direction.
(d) this can't be true.
So the answer is (d) negative.
The added weight of the sand puts more downward pressure on the wheels contacting the rails, which would cause the trains speed to decrease.
Answer:
See below
Explanation:
Vertical position is given by
df = do + vo t - 1/2 a t^2 df = final position = 0 (on the ground)
do =original position = 2 m
vo = original <u>VERTICAL</u> velocity = 0
a = acceleration of gravity = 9.81 m/s^2
THIS BECOMES
0 = 2 + 0 * t - 1/2 ( 9.81)t^2
to show t =<u> .639 seconds to hit the ground </u>
During this .639 seconds it flies horizontally at 10 m/s for a distance of
10 m/s * .639 s =<u> 6.39 m </u>
