18. a. Derive an expression for time period of a simple pendulum using dimensional analysis. b. A calorie is a unit of heat or energy and it equals about 4.2 J where 1 J = 1 kg m2 s-2. Suppose we

employ a system of units in which the unit of mass equals α kg, the unit of length equals β m, the unit of time

is γ s. Show that a calorie has a magnitude of 4.2 α-1 β-2 γ2 in terms of the new units

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when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min

b. false

explanation:

suppose a rock in free fall is dropped off a cliff. after falling for 5 seconds, its speed would not be 100 m/s.