A spring balance is a simple device consisting of a coiled spring which gets stretched when a load is hanged at its lower end. Stretching of spring is measured by a pointer moving on a graduated scale. The reading on scale gives the magnitude of force. Now a string is tied around a wooden block and is pulled by a spring balance as shown in figure.
Answer the following question.
(a) Which force can be measured by a spring balance when a load is hanged at its lower end? What is its unit?
(b) State the factors that determine the magnitude of force acting on an object?
(c) The reading on spring balance will give you a measure of which force when the block shown in the figure just begins to move?
(d) If now an additional weight is put on the block what change will you observe in reading of spring balance? Why?
Answers
Answer:
When we apply force 1N on one side, spring balance will get accelerated in direction of that force.
To get the reading on spring balance, we must apply equal and opposite force on other end.
In case of actual reading, suppose spring balance is hung from support, when we put mass in pan, same reaction as that of weight is applied by spring balance on support.
So, in equilibrium, if we apply force F on both sides of balance, then it will read as "F".
Here,
spring balance will now read 1N.
Answer:
(a) When load is hanged at its lower end, frictional force (static friction as the object is stationary) can be measured. It's unit is Newtons.
(b) i. The nature of the surfaces in contact
ii. Force pressing the two surfaces together
(c) When the block in the figure jist began to move,it gave the measure of sliding friction.
(d) When an additional weight is put on the block,the reading i.e force will increase because force pressing two surfaces together increased.
Explanation:
When the spring balance it used perpendicularly, it takes gravitational force into account and the opposing force, here the opposing force is friction.