Speed of the car given initially
v = 18 m/s
deceleration of the car after applying brakes will be
a = 3.35 m/s^2
Reaction time of the driver = 0.200 s
Now when he see the red light distance covered by the till he start pressing the brakes


Now after applying brakes the distance covered by the car before it stops is given by kinematics equation

here
vi = 18 m/s
vf = 0
a = - 3.35
so now we will have


So total distance after which car will stop is


So car will not stop before the intersection as it is at distance 20 m
m = mass of the person = 82 kg
g = acceleration due to gravity acting on the person = 9.8 m/s²
F = normal force by the surface on the person
f = kinetic frictional force acting on the person by the surface
μ = Coefficient of kinetic friction = 0.45
The normal force by the surface in upward direction balances the weight of the person in down direction , hence
F = mg eq-1
kinetic frictional force on the person acting is given as
f = μ F
using eq-1
f = μ mg
inserting the values
f = (0.45) (82) (9.8)
f = 361.6 N
Answer:
1.995 m
Explanation:
Distance of penny as seen by the person = 5 m
Height of person from water surface = 3.50 m
Apparent depth of penny = 5 - 3.50 = 1.5 m
refractive index of water, n = 1.33
real depth / apparent depth = n
real depth = 1.33 x 1.5 = 1.995 m
Thus, the actual depth of water at that point is 1.995 m.
Time period = 1 / frequency
Time period = 1 / 250 th of a second
Answer:
correct option is A. Resonance
Explanation:
solution
vibrations in the tube are caused by the Resonance because Resonance cause of sounds production in the musical instrument
As if resonance ( hollow cylindrical tube) immerse in cylinder of water and force in to vibration by tuning fork
As tines of tuning fork vibrate at natural frequency and it create sound wave that impinged up on opening of resonance tube
so correct option is A. Resonance