Answer:
V= 6.974 m/s
Explanation:
Component( box) weight acting parallel and down roof 88(sin39.0°)=55.4 N
Force of kinetic friction acting parallel and up roof = 18.0 N
Fnet force acting on tool box acting parallel and down roof
Fnet= 55.4 - 18.0
Fnet=37.4 N
acceleration of tool box down roof
a = 37.4(9.81)/88.0
a= 4.169 m/s²
d = 4.90 m
t = √2d/a
t= √2(4.90)/4.169
t= 1.662 s
V = at
V= 4.169(1.662)
V= 6.974 m/s
Answer:

Explanation:
using the law of the conservation of energy:


where K is the spring constant, x is the spring compression, N is the normal force of the block,
is the coefficiet of kinetic friction and d is the distance.
Also, by laws of newton, N is calculated by:
N = mg
N = 3.35 kg * 9.81 m/s
N = 32.8635
So, Replacing values on the first equation, we get:

solving for
:

Answer:
141.78 ft
Explanation:
When speed, u = 44mi/h, minimum stopping distance, s = 44 ft = 0.00833 mi.
Calculating the acceleration using one of Newton's equations of motion:

Note: The negative sign denotes deceleration.
When speed, v = 79mi/h, the acceleration is equal to when it is 44mi/h i.e. -116206.48 mi/h^2
Hence, we can find the minimum stopping distance using:

The minimum stopping distance is 141.78 ft.
Charles Law
Explanation:
Step 1:
It is given that the original volume of the gas is 250 ml at 300 K temperature and 1 atmosphere pressure. We need to find the volume of the same gas when the temperature is 350 K and 1 atmosphere pressure.
Step 2:
We observe that the gas pressure is the same in both the cases while the temperature is different. So we need a law that explains the volume change of a gas when temperature is changed, without any change to the pressure.
Step 3:
Charles law provides the relationship between the gas volume and temperature, at a given pressure
Step 4:
Hence we conclude that Charles law can be used.
Electric power most likely. It can be a generator for a power plant if needed. Hope this helped. Sorry if it didn't.