9th Physics Chapter 4 Constructed Response Questions
9th Physics New Chapter 4 Constructed Response Questions
4.1 A car travels at the same speed around two curves with different radii. For which radius the car experience more centripetal force? Prove your answer.
If same car travels with same speed around two curves with different radii, for smaller radius car will experience greater centripetal force. Because mass and speed will be constant and radius of the circle will be inversely proportional to the centripetal force.
$$F\;=\;\frac{m\;v^2}r\\If\;m\;and\;v\;are\;cons\tan t\\then\\F\;\propto\frac1r$$
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4.2 A ripe mango does not normally fall from the tree. But when the branch of the tree is shaken, the mango falls down easily. Can you tell the reason?
It happens due to inertia. When branch moves, mango want to stay in its original state due to inertia. Due to this, stem of the mangoes experiences a force and the mango falls down. This is an example of Newton’s first law of motion.
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4.3 Discuss the concepts of stability and centre of gravity in relation to objects topping over. Provide an example where an object’s centre of gravity affects its stability, and explain how altering its base can influence stability.
Stability means after tilting how likely the object is to return to its original position. Centre of gravity of an object is a point where the entire weight of the object appears to be acting.
A cupboard in a room is has high centre of gravity. So a small push can tilt it. When it tilts, centre of gravity can move outside the base, causing the cupboard to topple over. If we increase the base, the vertical line through the centre of gravity still falls inside the base, so cupboard will not topple.
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4.4 Why an accelerated body cannot be considered in equilibrium?
An accelerated body cannot be considered in equilibrium because acceleration means forces are unbalanced.
A body is said to be in equilibrium if all the forces acting on it are balanced and its state of motion does not change
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4.5 Two boxes of the same weight but different heights are lying on the floor of a truck. If the truck makes a sudden stop, which box is more likely to tumble over? Why?
Two boxes of the same weight but different heights are lying on the floor of a truck. If the truck makes a sudden stop the taller box will more likely tumble over due to its higher centre of gravity.
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