Answer:
Work done required is 3567.2 J
Explanation:
Given :
Length of chain, l = 72 m
Mass of chain, M = 29 kg
Linear mass density of chain, μ = 
= 
= 0.40 kg/m
Let x be the length of the chain which lift to the top of the building.
Work done required to lift the chain is equal to the potential energy of the chain.
W = ∫μg (72 - x ) dx
Here g is acceleration due to gravity.
The limit of integration is from 0 to 14.
W = μg ( 72x - x²/2)
Substitute 0.40 kg/m for μ, 9.8 m/s² for g and 14 m for x in the above equation.
W = 
W = 3567.2 J
Explanation:
The relative velocity is the velocity of the athlete relative to the ground plus the velocity of the javelin relative to the athlete.
v = 4.2 m/s + 10.3 m/s
v = 14.5 m/s
A sound wave is the answer
Answer: 4
Explanation: because 0s aren’t significant and after the decimal point, there was to be a value greater than 0 than the rest are sig figs.
<span>3.2 grams
The first thing to do is calculate how many half lives have expired. So take the time of 72 seconds and divide by the length of a half life which is 38 seconds. So
72 / 38 = 1.894736842
So we're over 1 half life, but not quite 2 half lives. So you'll have something less than 12/2 = 6 grams, but more than 12/4 = 3 grams.
The exact answer is done by dividing 12 by 2 raised to the power of 1.8947. So let's calculate 2^1.8947 power
= 12 g / (e ^ ln(2)*1.8947)
= 12 g / (e ^ 0.693147181 * 1.8947)
= 12 g / (e ^ 1.313305964)
= 12 g / 3.718446464
= 3.227154167 g
So rounded to 2 significant figures gives 3.2 grams.</span>
