IIT JEE , AIEEE Forum - Physics , Mechanics - hc verma [Admin]: Kinematics, Q-21

lovegirl

hi
cud u plz tell me q. no 21, 31 nd 44 on pg 52 nd 53 , kinematics of hc verma

Moderator

Dear Lovegirl,

Sorry but you can ask only one question at a time. We are forwarding Q.21 to the experts. For rest of the ques. please post them as a separate query one by one.

vaibhav1729

u can hav a lok over d problem 7 pg42 hc verma toget d basic idea for 21 q

cvramana

Problem 21. H.C.VERMA

Let the distance traveled by the motorbike before the police could catch up be x. Then the equation of motion for bike is

X = 20 t -------------(1)

The equation of motion for the police jeep is

X = 25 (t - 10) --------------(2)

Solving we get t = 50 and x = 1000 m or 1 KM.

Problem 31. H.C.VERMA.

Initial relative velocity between the coin and the elevator is 0.

Relative acceleration between the lift and the coin is (g - a).

Therefore

6 = 0.5 (g - a) t² -------------(1)

put t = 1.

We get g - a = 12 -----------(2)

Since the units are in FPS, g= 32.

a = 32 - 12 = 20 ft / s².

Topic ID: 44

Let it strike n^th bench.

Therefore y = n and x = 110 + n

Also y = x tan 53⁰ - g x² / 2 (35)² cos ² (53⁰)

Solving the above equations we get the answer.

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