C) alternating current .
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B)direct current </span>
Answer:
1470kgm/s
Explanation:
Given parameters:
Mass of the rock = 50kg
Time taken for the free fall = 3s
Unknown:
Change in momentum = ?
Solution:
The change in momentum will be difference between the ending momentum and finishing momentum.
Momentum is the product of mass and velocity
Momentum = mass x velocity
Initial momentum = 0, the velocity is 0
Final momentum = mass x final velocity
let us find the final velocity;
V = U + gt
V is the final velocity
U is the initial velocity
g is the acceleration due to gravity = 9.8m/s²
t is the time
V = 0 + 9.8x3 = 29.4m/s
So;
Change in momentum = 50 x 29,4 = 1470kgm/s
ANSWER
Both trucks will move together with speed v = 6.67 m/s
so correct answer will be
The speed of the combined vehicles is less than the initial speed of the truck.
EXPLANATION
As we know that there is no external force on the system of two trucks
So here momentum of the two trucks before collision and after collision will remain same
So here we will have

so here we will have




now we will have


so correct answer will be
The speed of the combined vehicles is less than the initial speed of the truck.