C.) A girl hangs by both hands, motionless, from a trapeze.
Answer:
γ = 0.06563 N / m
9.78% difference
Explanation:
Solution:-
- Surface tension is the ability of any fluid to resist any external force which causes a decreases in surface area of the impact area due to inward compressive forces. These compressive forces occur due to cohesive nature of the fluid molecules.
- Mathematically, surface tension ( γ ) is defined as the force felt per unit length by the fluid.
γ = F / L
Where,
F: Force imparted
L: The length over which force is felt
- We are given the mass ( M ) of ( n = 100 ) water droplets to e 3.78 g. The mass of a single droplet ( m ) can be evaluated as follows:
m = M / n
m = 3.78 / 100
m = 0.0378 g
- The force ( F ) imparted by a single drop of water from the burette can be determined from the force balance on a single droplet. Assuming the distance over which the drop falls is negligible and resistive forces are negligible. Then the only force acting on the droplet is due to gravity:
F = m*g
F = 0.0378*9.81*10^-3
F = 0.000370818 N
- The length over which the force is felt can be magnified into a circular area with diameter equal to that of a single droplet ( d ). The circumferential length ( L ) of the droplet would be as follows:
L = π*d
L = π*( 0.0018 )
L = 0.00565 m
- Then the surface tension would be:
γ = F / L
γ = 0.000370818 / 0.00565
γ = 0.06563 N / m
- The tabulated value of water's surface tension is given as follows:
γa = 0.07275 N/m
- We will determine the percentage difference between the value evaluated and tabulated value as follows:

- The %difference between is within the allowable practical limits of 10%. Hence, the evaluated value ( γ = 0.06563 N / m ) can be accepted with 9.78% error.
Answer: A) O N
Explanation:
An object in motion will maintain its state of motion. The presence of an unbalanced force changes the velocity of the object.
2.57 joule energy lose in the bounce
.
<u>Explanation</u>:
when ball is the height of 1.37 m from the ground it has some gravitational potential energy with respect to hits the ground
Formula for gravitational potential energy given by
Potential Energy = mgh
Where
,
m = mass
g = acceleration due to gravity
h = height
Potential energy when ball hits the ground
m= 0.375 kg
h = 1.37 m
g = 9.8 m/s²

Potential Energy = 5.03 joule
Potential energy when ball bounces up again
h= 0.67 m

Potential Energy = 2.46 joule
Energy loss = 5.03 - 2.46 = 2.57 joule
2.57 joule energy lose in the bounce
His model was also called the Planetary model