Answer:
(I). The effective cross sectional area of the capillaries is 0.188 m².
(II). The approximate number of capillaries is 
Explanation:
Given that,
Radius of aorta = 10 mm
Speed = 300 mm/s
Radius of capillary 
Speed of blood 
(I). We need to calculate the effective cross sectional area of the capillaries
Using continuity equation

Where. v₁ = speed of blood in capillarity
A₂ = area of cross section of aorta
v₂ =speed of blood in aorta
Put the value into the formula



(II). We need to calculate the approximate number of capillaries
Using formula of area of cross section


Put the value into the formula


Hence, (I). The effective cross sectional area of the capillaries is 0.188 m².
(II). The approximate number of capillaries is 
Answer:
0.000001 kg
Explanation:
because 1 kg equal 1,000,000 milligrams
we take
which equals 0.000001 kg
Either convection or thermal energy
The tension in each of the ropes is 625 N.
Draw a free body diagram for the bag of food as shown in the attached diagram. Since the bag hangs from the midpoint of the rope, the rope makes equal angles θ with the horizontal. The tensions <em>T</em> in both the ropes are also equal.
Resolve the tension T in the ropes into horizontal and vertical components T cosθ and T sinθ respectively, as shown in the figure. At equilibrium,
......(1)
Calculate the value of sinθ using the right angled triangles from the diagram.

Substitute the value of sinθ in equation (1) and simplify to obtain T.

Thus the tension in the rope is 625 N.
Answer:
Speed, v = 7.83 m/s
Explanation:
It is given that,
Length of the bridge, l = 5 m
The road on the far side is 2.0 m lower than the road on this side, x = 2 m
The horizontal distance covered by the car is 5 meters and the vertical distance covered by the car is 2 meters.
Initial speed of the car, u = 0
Let t is the time taken by the car . Using the second equation of motion as :
For vertical distance :


Let v is the velocity to jump the stream. It is given by :
Horizontal distance, d = 5 m

v = 7.83 m/s
So, the car should travel with a speed of 7.83 m/s. Hence, this is the required solution.