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The best thermal conductor is b. metal
Momentum = (mass) x (speed)
Change in momentum = (force) x (time)
The initial momentum is (mass) x (speed) = 2500x 25 = 62,500 kg-m/s.
Since you want to <u>stop</u> the vehicle, that number is also the required <em>change</em>
in momentum ... you want the vehicle to wind up with zero momentum.
62,500 = (force) x (time) = 20 x force
Divide each side by 20 :
force = 62,500 / 20 = <em>3,125 newtons </em>
Answer:
dimensions of k are kg / s^2
Explanation:
F=ma (Newton's second law)
F=-kx (Hooke's law)
so equate both
-kx = ma
k = -ma/x
= mass * acceleration / distance (dimensions, -1 has no dimension)
= kg * m/s^2 / m
= kg / s^2
