Question

Камень пущенный по льду ударом клюшки остановился через 4с после удара на расстоянии 18м от места удара. Определить силу трения между камнем и льдом, если масса камня 120г

Answer 1

После удара действует только  сила трения, которую можно рассчитать по  формуле  F=m*V0/t   S=V0*t/2    V0=2*S/t

F=m*2*S/t^2=0,12*2*18/4^2=0,27 H

Answer 2

Problem Analysis

We are given the following information: - A stone is thrown on ice with a force from a hockey stick. - The stone comes to rest 4 seconds after the impact. - The stone stops at a distance of 18 meters from the point of impact. - The mass of the stone is 120 grams.

We need to determine the frictional force between the stone and the ice.

Solution

To solve this problem, we can use the equations of motion. The key equation we will use is:

v^2 = u^2 + 2as

Where: - v is the final velocity of the stone (which is 0 since it comes to rest) - u is the initial velocity of the stone - a is the acceleration of the stone - s is the distance traveled by the stone

We can rearrange this equation to solve for the acceleration:

a = (v^2 - u^2) / (2s)

Since the stone comes to rest, the final velocity (v) is 0. Therefore, the equation becomes:

a = -u^2 / (2s)

Now, we can calculate the acceleration of the stone using the given information.

Calculation

Given: - Mass of the stone (m) = 120 grams = 0.12 kg - Distance traveled by the stone (s) = 18 meters - Time taken for the stone to come to rest (t) = 4 seconds

We know that acceleration (a) is the rate of change of velocity, which can be calculated using the formula:

a = (v - u) / t

Since the stone comes to rest, the final velocity (v) is 0. Therefore, the equation becomes:

a = -u / t

Now, we can calculate the acceleration of the stone:

a = -u / t = -0 / 4 = 0 m/s^2

The acceleration of the stone is 0 m/s^2.

Now, we can calculate the frictional force (F) using the formula:

F = m * a

Substituting the values:

F = 0.12 kg * 0 m/s^2 = 0 N

Therefore, the frictional force between the stone and the ice is 0 Newtons.

Conclusion

The frictional force between the stone and the ice, when the stone comes to rest 4 seconds after the impact at a distance of 18 meters from the point of impact, is 0 Newtons.