Answer:
Explanation:
We know that:
where 
is the initial energy, 
is the final energy and 
is the energy lost due to friction.
so:
Where M is the mass and V is the velocity of the runner, so:
Answer:
Isaac walked a distance of 5 blocks, and his displacement was 3 blocks north.
Explanation:
Distance is what he covered from the beginning, while displacement was what he covered in a specific direction
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.
-- A change in speed can be either speeding up or slowing down. These effects can be caused by the gas pedal or the brake pedal.
-- Velocity is made of the car's speed and direction. These can be changed by the gas pedal, the brake pedal, or the steering wheel.
