Explanation:
initial velocity= 80km/hr = 22.22 m/s
distance= 40m
Final velocity= 0m/s ( as it needs to be stopped)
<u>Using </u><u>third </u><u>equation </u><u>of </u><u>motion</u><u>,</u>
=> 2as = v² - u²
=> 2a * 40m = 0² - (22.22 m/s)²
=> a = - 493.72/80 m/s²
=> a = - 6.17m/s²
<u>Using </u><u>first </u><u>equation </u><u>of </u><u>motion</u><u>,</u>
=> a = v - u /t
=> -6.17 = 0-22.22/t
=> t = -22.22/-6.17 s
=> t ≈ 3.7 s = stopping time
Answer: C and D
Explanation: One of the first rule for total internal reflection to occur is that the ray must move from a dense to a less dense medium, hence refractive index of medium a must be greater than that of b.
When a ray moves from a dense to a less dense medium, the refracted ray moves away from the normal thus increasing the size of the angle of refraction (total internal refraction occurs when the angle of refraction is 90° and the angle of incidence at this point is known as the critical angle), hence the angle of incidence must be greater than the critical angle.
These points verifies option C and D
-- light energy (the whole purpose of current through the bulb)
-- heat energy (it can't be avoided)
To solve this problem we must keep in mind the concepts related to angular kinematic equations. For which the angular velocity is defined as
Where
Final angular velocity
Initial angular velocity
Angular acceleration
t= time
In this case we do not have a final angular velocity, then
Re-arrange for 
Therefore the mangitude of the angular aceleration is 5449.1rad/s²
