Since the bulb consumes 100 watts of power and its efficiency is 95%,
it generates 95 watts of light energy and 5 watts of heat energy whenever
it's turned on.
5 watts means 5 joules of energy per second.
(2.5 hours) x (3,600 seconds/hour) = 9,000 seconds
(9,000 seconds) x (5 joules/second) = 45,000 joules of heat in 2.5 hours
Answer:
option D
Explanation:
given,
Intensity of sound = 20 dB
distance = 15 m
intensity of sound is increased to = 50 dB
distance between the sound level = ?
Using relation
L₁ = 20 dB L₂ = 50 dB r₁ = 15 m r₂ = ?
r₂ = 0.47 m
r₂ = 47 cm
hence, the correct answer is option D
Answer:
They experience the same magnitude impulse
Explanation:
We have a ping-pong ball colliding with a stationary bowling ball. According to the law of conservation of momentum, we have that the total momentum before and after the collision must be conserved:
where is the initial momentum of the ping-poll ball
is the initial momentum of the bowling ball (which is zero, since the ball is stationary)
is the final momentum of the ping-poll ball
is the final momentum of the bowling ball
We can re-arrange the equation as follows or
which means (1) so the magnitude of the change in momentum of the ping-pong ball is equal to the magnitude of the change in momentum of the bowling ball.
However, we also know that the magnitude of the impulse on an object is equal to the change of momentum of the object:
(2) therefore, (1)+(2) tells us that the ping-pong ball and the bowling ball experiences the same magnitude impulse:
