Answer:
(A) 7.9 m/s^{2}
(B) 19 m/s
(C) 91 m
Explanation:
initial velocity (U) = 0 mph = 0 m/s
final velocity (V) = 85 mph = 85 x 0.447 = 38 m/s
initial time (ti) = 0 s
final time (t) = 4.8 s
(A) acceleration = 
= 
= 7.9 m/s^{2}
(B) average velocity = 
=
= 19 m/s
(C) distance travelled (S) = ut + 
= (0 x 4.8) + 
= 91 m
A ionosphere is a layer of the earths atmosphere that is ionized by solar and cosmic radiation <span />
Answer:
Following are the answer to this question:
Explanation:
Formula:
Calculating point A:
when the value is 
Calculating point B:
when the value is 
Calculating point C:
when the value is 
Calculating point D:
when the value is 
Calculating point E:
when the value is 
Answer: D
Explanation:
Let us examine the given actions to see which ones generate heat and sound energy from mechanical energy.
A) Stretching a string.
The mechanical stretching creates tension in the string, which is released when the tension is removed. The generation of thermal or sound energy is minimal or negligible.
B) Squeezing a sponge ball
The sponge ball experiences compressive loading. This generates minimal or no heat and sound energy.
C) Throwing a ball upwards in the air
Air friction generates minimal or no heat at low velocities. At low velocities the pressure waves are too small to generate sound.
D) Striking a hammer on a nail.
A tremendous amount of force is applied over a small area to generate very high stresses that are in the plastic zone. A high amount of thermal energy is generated and the localized disturbance of the air generates audible sound.
This is the correct situation.
