perimeter of a rectangle = 2(L+B)
90=2(L+B)
90/2=L+B
45=L+B
Given that,
Radius of track, r = 50 m
time , t = 9 s
velocity, v = ?
Distance covered by car in one lap around a track is equal to the circumference of the track.
C = 2 π r = 2 * 3.14 * 50
C = 314.159 m
Distance covered by car, s = 314.159 m
Velocity = distance/ time
V = 314.159 / 9
V = 34.9 m/s
The average velocity of car is 34.9 m/s.
Answer:
c. Sound travels slower than light.
Explanation:
We see any thing because of the light emitted or reflected by it. Whereas the sound is carried by the sound waves. The speed of light is more than the speed of sound. This is the reason the family saw the fireworks first and then heard the sound.
The same can be experienced during the sighting of a Jet plane or a rocket where, we see them way before we can hear the roaring sound of its engines.
For the answer to the question above, this is the maximum displacement, the spring has only elastic potential energy.
spring is constant @ 5 N/m
maximum displacement = 2 cm = 0.02 m
elastic potential energy = 1/2 kx²
= 0.5 x 5 x 0.02²
So the answer would be
= 0.001 Joules