Achild is sliding on a sled at 1.5 m/s to the right. you stop the sled by pushing on it for 0.50 s in a direction opposite to its motion. if the mass of the child and sled is 35 kg, what average force do you need to apply to stop the sled? use the concepts of impulse and momentum.

The average force I need to apply to stop the sled is 105 N

Explanation:

given information:

velocity of the slide, = 1.5 m/s

time to stop the sled, t = 0.5s

mas of both sled ad a child, m = 35 kg

The question instructed to use the concepts of impulse and momentum. Impulse, Δp is the change in momentum

Δp = FΔt

where

Δp = change in momentum

F = applied force

Δt = elapsed time

so,

Δp = FΔt

mv = FΔt

F = mv/Δt

  = 35 x 1.5/0.5

  = 105 N

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.