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.
Answer:
(D) None
Explanation:
The force of gravity is the force pulling every element of matter together. The more the matter the higher the force of gravity.
Examples of this force at work are;
- The force that causes an apple to fall from the tree
- The force that causes a rock to roll downside a hill
- The force causing people to walk on the earth surface instead of floating
The force that facilitates a pen on your hand to write on a paper is friction force between the pen and the paper. Gravitational force acts downwards thus force applied on an object beside you is not the force of gravity.
Answer:
it's C
Explanation:
have a nice day............
Answer:
Approximately
.
Explanation:
The refractive index of the air
is approximately
.
Let
denote the refractive index of the glass block, and let
denote the angle of refraction in the glass. Let
denote the angle at which the light enters the glass block from the air.
By Snell's Law:
.
Rearrange the Snell's Law equation to obtain:
.
Hence:
.
In other words, the angle of refraction in the glass would be approximately
.
Answer:
lambda = 343 m/s divided by 340 Hz = 1.009 seconds
Hope it helps and have a wonderful day!