A hockey puck has a mass of 0.118 kg and is at rest. A hockey player makes a shot, exerting a constant force of 28.0 N on the puck for 0.16 s. With what speed does it head toward the goal?
Force = change in momentum / change in time
28 = m v/t = .118 v / .16
v = 28 (.16)/.118 = 38 m/s
To find the speed at which the hockey puck heads toward the goal, we can use Newton's second law of motion, which states that the net force acting on an object is equal to the mass of the object multiplied by its acceleration (F = ma). We can rearrange this equation to solve for acceleration:
a = F / m
where F is the force exerted on the puck and m is the mass of the puck.
In this case, the force exerted on the puck is 28.0 N and the mass of the puck is 0.118 kg. Plugging these values into the equation, we get:
a = 28.0 N / 0.118 kg
Now we need to calculate the acceleration.
a ≈ 237.288 N/kg
Since the force is constant, the acceleration is also constant for the duration of the shot.
Next, we need to calculate the final velocity of the puck. We can do this using the equation:
v = u + at
where v is the final velocity, u is the initial velocity (in this case, 0 m/s since the puck is at rest), a is the acceleration, and t is the time for which the force is applied.
In this case, u = 0 m/s, a ≈ 237.288 N/kg (calculated above), and t = 0.16 s. Plugging these values into the equation, we get:
v = 0 + (237.288 N/kg)(0.16 s)
v ≈ 37.966 m/s
Therefore, the hockey puck heads toward the goal at a speed of approximately 37.966 m/s.