Answer:
6.32s
Explanation:
Given parameters:
Length of track and distance covered = 200m
Acceleration = 10m/s²
Unknown:
Time taken to cover the track = ?
Solution:
To solve this problem, we apply one of the motion equations as shown below:
S = ut + at²
S is the distance covered
t is the time taken
a the acceleration
u is the initial velocity
The initial velocity of Superman is 0;
So;
S = at²
200 = x 10 x t²
200 = 5t²
t² = 40
t = 6.32s
The final kinetic energy of the ball is 2.45 J
Explanation:
We can solve this problem by using the law of conservation of energy.
In absence of frictional effect, the mechanical energy of the apple must be conserved during the fall. So we can write:
where :
is the initial potential energy, at the top
is the initial kinetic energy, at the top
is the final potential energy, at the bottom
is the final kinetic energy, at the bottom
By explicing the potential energy, we can rewrite the equation as:
where:
m = 0.5 kg is the mass of the apple
is the acceleration of gravity
is the initial height
is the final height
The initial kinetic energy is zero, since the ball starts from rest:
Therefore we can solve the equation for , the final kinetic energy of the ball:
Learn more about kinetic energy and potential energy:
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Answer:
option A
Explanation:
given,
Kinetic energy of the car = 2000 J
speed of the car is doubled
we know,
........(1)
now, speed of the car is doubled
v' = 2 v
from equation (1)
Hence, the Kinetic energy would be equal to 8000 J.
The correct answer is option A.