Average speed = (total distance covered) / (time to cover the distance)
total distance covered = (4km + 2km + 1km) = 7 km
time to cover the distance = (32min + 22min + 16min) = 70 min
Average speed = (7 km) / (70 min)
Average speed = 0.1 km/minute
Answer:
Calculating Coefficient of friction is 0.229.
Force is 4.5 N that keep the block moving at a constant speed.
Explanation:
We know that speed expression is as
.
Where,
is initial speed, V is final speed, ∆s displacement and a acceleration.
Given that,
=3 m/s, V = 0 m/s, and ∆s = 2 m
Substitute the values in the above formula,

0 = 9 - 4a
4a = 9

is the acceleration.
Calculating Coefficient of friction:


Compare the above equation

Cancel "m" common term in both L.H.S and R.H.S





Hence coefficient of friction is 0.229.
calculating force:


F = 4.5 N
Therefore, the force would be <u>4.5 N</u> to keep the block moving at a constant speed across the floor.
Answer:
The angle of incidence when the reflected ray is perpendicular to the incident ray = 45°
Explanation:
According to Snell's Law,
n₁ sin θ₁ = n₂ sin θ₂
When the angle between the incident ray and reflected ray is 90°, the angle of incidence is θ₁ and the angle of reflection, θ₂ = 90° - θ₁ and the index of refraction in the Snell's Law for both media would be the same, n₁ = n₂ = n
n sin θ₁ = n sin (90° - θ₁)
Note that from trigonometric relations,
Sin (90° - θ₁) = cos θ₁
n sin θ₁ = n cos θ₁
(sin θ₁)/(cos θ₁) = 1
tan θ₁ = 1
θ₁ = arctan 1 = 45°
Hope this Helps!!!
Answer:
<em>They represent kinetic energy</em>
Explanation:
<u>Kinetic Energy
</u>
A body can do work due to some of its attributes or states. For example, its mass can do work if used to provide energy, if the object is at a certain height respect to some reference level, it can do work when going downwards (potential energy), if the object moves at a certain speed, it can do work when transferring part of its speed to other objects. It's called kinetic energy and is given by

Both runners are moving in a horizontal path, thus they have kinetic energy, given by the above equation. If they could jump below ground level, then they will also have potential energy