dynamics
A curling stone has a mass of 20kg. a curler pushed the stone across the ice to launch it down the rink.
a)if the curler starts to move the stone by pushing it with 15N, what is the stones initial acceleration?
b)once moving, how much force is required to keep the stone moving at a uniform velocity?
To answer these questions, we can use Newton's second law of motion, which states that the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass.
a) To find the stone's initial acceleration, we need to divide the net force applied by the mass of the stone. In this case, the net force applied is 15N, and the mass of the stone is 20kg.
Acceleration (a) = Net Force (F) / Mass (m)
a = F / m
a = 15N / 20kg
a = 0.75 m/s²
Therefore, the stone's initial acceleration is 0.75 m/s².
b) Once the stone is moving at a uniform velocity, it means that the net force acting on it is zero. According to Newton's first law of motion (also known as the law of inertia), an object at rest or moving at a constant velocity will continue to do so unless acted upon by an external force.
Since the stone's velocity is constant, the acceleration is zero. From Newton's second law, we know that when acceleration is zero, the net force must also be zero.
Therefore, to keep the stone moving at a uniform velocity, no force is required because no net force is acting on it.