1. A crowbar of length 1.80m is used move a rock of mass 310kg. The fulcrum is 20cm from the load . Calculate (a) the VR neglecting the weight of crowbar, (b) MA ,(c) effort E and efficiency.
2.In the above problem the weight of bar is not negligible.Its mass is 20kg.The torque exerted by this weight will reduce the efforts required .(a) Calculate this effort,equating torques ,the VR is the same as the dimensions remain the same as in problem 6.(b) Calculate the actual MA and (c) actual efficiency. (d)Explain briefly if the law of conservation of energy is violated.
3.In the see-saw problem (problem no.2), the big brother lowers (swings) himself from the horizontal level by 50cm in 1 second , then comes back to the horizonal level in 1 second and then up above the horizontal level by 50cm in 1 second. Then he continues to swing up and down merrily. (a.) What is the maximum height (above the horizontal) to which the little brother goes up? (b.)What is the average speed of the little brother in one complete swing? (c.) What is the average velocity in one complete swing?
from the ground floor a man comes up to the fourth floor of a building using a staircase another person comes up to the same floor using the elevator. neglect friction and compare work done in the two cases
1.A see-saw has a 40kg boy sitting at a distance of 80cm from one end and his little brother of 30kg is counter balanced on the other side. The fulcrum is in the middle of the uniform plank of length 4.0 .How far is the little brother from the other end of the see-saw ?
2.In the above problem on see-saw the mass of the plamk is 10kg. (a) What is the force exerted(magnitude and direction) on the support system by the see-saw and the children? (b.)What is the normal reaction on the see-saw? Do both calculations for the see-saw remaining horizontal.
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