Answer:
a) 3.37 x 
b) 6.42kg/
Explanation:
a) Firstly we would calculate the volume of the metal using it`s weight in air and water , after finding the weight we would find the density .
Weight of metal in air = 50N = mg implies the mass of metal is 5kg.
Now the difference of weight of the metal in air and water = upthrust acting on it = volume (metal) p (liquid) g = V (1000)(10) = 14N. So volume of metal piece = 14 x
. So density of metal = mass of metal / volume of metal = 5 / 14 x
= 3.37 x 
b) Water exerts a buoyant force to the metal which is 50−36 = 14N, which equals the weight of water displaced. The mass of water displaced is 14/10 = 1.4kg Since the density of water is 1kg/L, the volume displaced is 1.4L. Hence, we end up with 3.57kg/l. Moreover, the unknown liquid exerts a buoyant force of 9N. So the density of this liquid is 6.42kg/
<h2>
Time needed is 2545.45 seconds.</h2>
Explanation:
We know equation for power

Here we need to find time when for a 22 kW steam engine to do 5.6 × 10⁷ J of work.
So
Work = 5.6 × 10⁷ J
Power = 22 kW = 22 x 10³ W
Substituting

Time needed is 2545.45 seconds.
Answer:
the average speed of the swimmer is 0.069 m/s.
Explanation:
Given;
complete distance around the park pine, d = 25 m
total lap completed, = 20 laps
time of laps completion, t = 7200 s
The total distance completed by the swimmer = 20 x 25 = 500 m
The average speed of the swimmer = distance / time
= (500 m) / (7200 s)
= 0.069 m/s.
Therefore, the average speed of the swimmer is 0.069 m/s.