A trolley moving along a horizontal road at a speed of 36 km / h begins to climb a hill

| January 11, 2021 | education

A trolley moving along a horizontal road at a speed of 36 km / h begins to climb a hill, the height of which is 4.2 m. What speed will the trolley have at the top of the hill? Resistance is neglected.

To find the speed of the used trolley on the top of the hill, we use the equality: En1 + Ek1 = Ek0 and m * g * h + m * V1 ^ 2/2 = m * V0 ^ 2/2, whence we express: V1 = √ (2 * (V0 ^ 2/2 – g * h)).
Constants and variables: V0 – speed of the used bogie on a horizontal road (V0 = 36 km / h (10 m / s)); g – acceleration due to gravity (g ≈ 10 m / s2); h is the height of the slide (h = 4.2 m).
Calculation: V1 = √ (2 * (V0 ^ 2/2 – g * h)) = √ (2 * (10 ^ 2/2 – 10 * 4.2)) = 4 m / s.
Answer: At the top of the hill, the cart used should have a speed of 4 m / s.



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