Answer:
They are equal
Explanation:
angle of incidence = angle of reflection
The answer is B (The second one). I'm not sure though.
Mechanical energy
I think
Answer:
It is the ratio of the density of a substance to the density of a given reference material.
Explanation:
<em>Specific gravity is also known as relative density.</em>
<u>To find the relative density of substance, you:</u>
- Divide the density of substance measured
- And divide that by the density of the reference
The given data is incomplete. The complete question is as follows.
At an accident scene on a level road, investigators measure a car's skid mark to be 84 m long. It was a rainy day and the coefficient of friction was estimated to be 0.36. Use these data to determine the speed of the car when the driver slammed on (and locked) the brakes. (why does the car's mass not matter?)
Explanation:
Let us assume that v is the final velocity and u is the initial velocity of the car. Let s be the skid marks and be the friction coefficient and m be the mass of car.
Hence, the given data is as follows.
v = 0, s = 84 m, = 0.36
According to Newton's law of second motion the expression for acceleration is as follows.
F = ma
= ma
= ma
a =
Also,
=
= 24.36 m/s
Thus, we can conclude that the speed of the car when the driver slammed on (and locked) the brakes is 24.36 m/s.