Answer:
The value is 
Explanation:
From the question we are told that
The magnitude of the horizontal force is 
The mass of the crate is 
The acceleration of the crate is 
Generally the net force acting on the crate is mathematically represented as

Here
is force of kinetic friction (in N) acting on the crate
So

=> 
Answer:
A. Materials with a low index of refraction cause light to refract very little.
Acceleration=(change in speed)/(time for the change). 43/0.28 = 153.6 m/s^2.
Answer:
1 C
Explanation:
The intensity of electric current is defined as

where
I is the current
q is the amount of charge transferred
t is the time interval during which the charge is transferred
For the lightning in this problem, we have
is the current
is the time interval
Solving the formula for q, we find the amount of charge transferred:

V= 1/3 π r²h
this is the formula for a cone hope this helps :)