Answer:
500 m/s
Explanation:
Momentum, p is a product of mass and velocity. From law of conservation of momentum, the initial momentum equals final momentum

Here m and v represent mass and velocity respectively and subscripts 1 and 2 represent car and barrier respectively
Therefore, the velocity of barrier will be 500 m/s
Answer:
Average speed, v = 25 m/s
Explanation:
It is given that,
Distance travelled by the object, d = 50 meters
Time taken, t = 2 seconds
Average speed is defined as the total distance divided by total time taken i.e.


v = 25 m/s
So, the sped of the object is 25 m/s. Hence, this is the required solution.
Newton's Second law of motion is
F = m * a ( force = mass * acceleration).
So if a is constant then a = F 1 / m1 and a = F2 / m2 then
F1 /m1 = F2 / m2 and if m1 > m2 then
F1 must be greater than F2.
Answer is C.
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