Short Answer TypeA uniform half metre rule balances horizontally on a knife edge at 29 cm mark when a weight of 20 gf is suspended from one end.
(i) Draw a diagram of the arrangement
(ii) What is the weight of the half metre rule?
A boy uses a single fixed pulley to lift a load of 50 kgf to some height. Another boy uses a single movable pulley to lift the same load to the same height. Compare the effort applied by them. Give a reason to support your answer.
Mechanical advantage (MA) given as,
The above equation indicates that Mechanical advantage and efforts are inversely proportional to each other.
The mechanical advantage of single fixed fully is 1.
For, single movable pulley, MA = 2
Load on both the pulleys =50 kgf
Hence, from the above,
In the case of single movable pulley,
MA > 1⇒ effort arm > load arm
and in the case of a single fixed pulley.
MA = 1⇒load arm = effort arm
∴ Effort applied in the single fixed pulley is less as compare single movable pulley.
A pulley system with VR = 4 is used to lift a load of 175 kgf through a vertical height of 15 m. The effort required is 50 kgf in the downward direction.
(g = 10 N kg-1) Calculate
(i) Distance moved by the effort
(ii) Work done by the effort
(iii) M.A. of the pulley system
(iv) Efficiency of the pulley system
Calculate the mass of ice needed to cool 150g of water contained in a calorimeter of mass 50 g at 32oC such that the final temperature is 5oC.
Specific heat capacity of calorimeter = 0.4J/goC Specific heat capacity of water = 4.2 J/goC Latent heat capacity of ice = 330 J/g
You have a choice of three metals A,B and C, of specific heat capacities 900 Jkg-1oC-1, 380 Jkg-1oC-1 and 460 Jkg-1oC-1 respectively, to make a calorimeter. Which material will you select? Justify your answer.
A radiation X is focused by a particular device on the bulb of a thermometer and mercury in the thermometer shows a rapid increase. Name the radiation X.
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