A car engine has___ power than a horse because a car engine does the same amount of work in___ time. Yasmin and Raj each had 10
2 answers:
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Answer:
option B
Explanation:
given,
height of building = 0.1 km
ball strikes horizontally to ground at = 65 m
speed at which the ball strike = ?
vertical velocity = 0 m/s
time at which the ball strike
t = 4.53 s
vertical velocity at the time 4.53 s = g × t = 9.8 × 4.53 = 44.39 m/s
horizontal velocity = =14.35 m/s
speed of the ball =
= 46.65 m/s
hence, the speed of the ball just before it strike the ground = 47 m/s
The correct answer is option B
The elastic potential energy of a spring is given by
where k is the spring's constant and x is the displacement with respect to the relaxed position of the spring.
The work done by the spring is the negative of the potential energy difference between the final and initial condition of the spring:
In our problem, initially the spring is uncompressed, so
. Therefore, the work done by the spring when it is compressed until 
is
And this value is actually negative, because the box is responsible for the spring's compression, so the work is done by the box.
where k is the spring's constant and x is the displacement with respect to the relaxed position of the spring.
The work done by the spring is the negative of the potential energy difference between the final and initial condition of the spring:
In our problem, initially the spring is uncompressed, so
And this value is actually negative, because the box is responsible for the spring's compression, so the work is done by the box.
The change in momentum of the car is 6000 kg m/s
Explanation:
According to the impulse theorem, the change in momentum of an object is equal to the impulse exerted on the object, therefore:
where
is the change in momentum
I is the impulse exerted
For the car in this problem, the impulse received is
I = 6000 kg m/s (in the forward direction)
Therefore, the change in momentum of the car is equal to this value:
(in the forward direction)
We can also calculate what is the new momentum of the car. In fact, the initial momentum is
And so, the new momentum is
Learn more about impulse and momentum:
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