Question

A 50 kg block of concrete is being slid across the ice, which has a coefficient of sliding friction of 0.1. A cable is attached to the right side and it is pulled with 49 Newtons of applied force. What is the acceleration?

Answer 1

The acceleration of the concrete block will be zero.

Step-by-step explanation:

As the block of concrete is being sliding along the ice, the applied force should be equal to the frictional force between the surface of concrete block with the sliding surface. So the applied force tend to equate with the static friction in order to pull the concrete block over the sliding ice.

So,

Applied force = Static Friction

The static friction is defined as the product of normal force acting on the object with the coefficient of friction of the sliding plane. Thus

`\text { Static friction }=\text { coefficient of friction } * \text { Normal force }`

And,

`\begin{aligned} \text { Normal force on the concrete } =m \text { of concrete } * \text {acceleration} \end{aligned}`

Thus,

`\text { Static friction }=\text { coefficient of friction } * m * \text { acceleration due to gravity }`

So,

`\text { Applied force }=\text { coefficient of friction } * m * \text { acceleration }`

Hence, the applied force is proportional to the acceleration due to gravity. In case the concrete block is pulled over the slide, the movement should be uniform so that the acceleration need to be zero for uniform motion of the concrete block over the ice.