Subject Experts Solutions for Exercise 2: PRACTICE QUESTIONS (COMPETITION WING)

A tailor purchased scissors of length $25 \mathrm{cm}$ through online shopping. He sent feedback to the manufacturer saying 'I cannot cut the Jeans cloth even if I apply my maximum force $83.3 \mathrm{N}$ on it, so please modify it without changing its length so that I can cut the Jeans cloth at least with my maximum effort.' If you are the manufacturer, how can you modify the scissors as per the feedback given by the tailor? Initially, the fulcrum is exactly midway between the two ends of the scissors and the minimum force required to cut the jeans cloth is $500 \mathrm{N}$. The position of the load should always be at $7.5 \mathrm{cm}$ from the free end of the load arm.

Krishna had parked his two-wheeler at a "no parking" place as he did not find any board regarding the notice NO PARKING. After some time, the traffic police took away his bike to a nearby police station, by lifting it with a rope attached to a pulley arrangement. If the mass of the bike is $150 \mathrm{kg}$, then what is its weight in dynes?

A farmer was cutting mangoes from a tree with a long stick of length $2 \mathrm{m}$. He cut almost all mangoes at the lower branches of the tree, and then he aimed to cut the mangoes at the higher branches of it. To do this he attached another stick to the top of the first stick so that the overall length increased by $1 \mathrm{m}$. If the distance between his hand's position is the same as before at $40 \mathrm{cm}$ and the weight of each mango is $5 \mathrm{N}$, then calculate the change in mechanical advantage of stick to do this, for the same effort of $20 \mathrm{N}$.

Anil has a two-wheeler that weighs $120 \mathrm{kg}$. After completing his work, he used to park his vehicle in the regular parking place which is connected to the ground with a ramp which just covers an open drain of width $4 \mathrm{m}$. If the length of the ramp is $5 \mathrm{m}$ then find the mechanical advantage of the ramp.

A body of mass $10 \mathrm{kg}$  is lifted by using a single fixed pulley as well as a single movable pulley. Compare the mechanical advantages of lifting the body using both pulleys.

A stone is placed in a stone cracker at $15 \mathrm{cm}$ from a fixed end; it experienced the force of $500 \mathrm{N}$. When force of $100 \mathrm{N}$ is applied at the free end of the stone cracker, calculate the length of the nutcracker.

Calculate the height of the plane if an inclined plane of length $10 \mathrm{m}$ is used to lift a load of $50$ dynes, by applying an effort of $15$ dynes.

A car was parked in 'No parking space' on the road. After some time, the traffic police took the car by lifting it with a rope attached to a pulley arrangement. Calculate the weight of car if its mass is $500 \mathrm{kg}$.