Answer:
The initial velocity is 50 m/s.
(C) is correct option.
Explanation:
Given that,
Time = 10 sec
For first half,
We need to calculate the height
Using equation of motion

....(I)
For second half,
We need to calculate the time
Using equation of motion



Put the value of h from equation (I)


According to question,


Put the value of t₁ and t₂



Here, g = 10
The initial velocity is


Hence, The initial velocity is 50 m/s.
Answer:
<h2>
96 Joules</h2>
Explanation:
We know that efficiency is the ratio of output power by input power. i.e. Efficiency describes the quality of machine or system how good it is.
Solution,
Energy input of system = 120 J
Efficiency = 80% = 
Now,
According to definition,
Efficiency = 
Cross multiplication:

Calculate the product

Hope this helps...
Good luck on your assignment...
<span>Answer: Force = 81.6 N
Explanation:
According to Newton's Second law:
F = ma --- (1)
Where F = Force = ?
m = Mass = 68 kg
a = Acceleration = 1.2 m/s^2
Plug in the values in (1):
(1) => F = 68 * 1.2
F = 81.6 N (The force needed to accelerate the skier at a rate of 1.2 m/s^2)</span>
Newton's 2nd law of motion:
Force = (mass) x (acceleration)
= (1,127 kg) x (6 m/s² forward)
= (1,127 x 6) newtons forward
= 6,762 newtons forward
______________________________
Momentum = (mass) x (speed)
= (69 kg) x (6 m/s)
= 414 kg-m/s
Answer:
the work is done by the gas on the environment -is W= - 3534.94 J (since the initial pressure is lower than the atmospheric pressure , it needs external work to expand)
Explanation:
assuming ideal gas behaviour of the gas , the equation for ideal gas is
P*V=n*R*T
where
P = absolute pressure
V= volume
T= absolute temperature
n= number of moles of gas
R= ideal gas constant = 8.314 J/mol K
P=n*R*T/V
the work that is done by the gas is calculated through
W=∫pdV= ∫ (n*R*T/V) dV
for an isothermal process T=constant and since the piston is closed vessel also n=constant during the process then denoting 1 and 2 for initial and final state respectively:
W=∫pdV= ∫ (n*R*T/V) dV = n*R*T ∫(1/V) dV = n*R*T * ln (V₂/V₁)
since
P₁=n*R*T/V₁
P₂=n*R*T/V₂
dividing both equations
V₂/V₁ = P₁/P₂
W= n*R*T * ln (V₂/V₁) = n*R*T * ln (P₁/P₂ )
replacing values
P₁=n*R*T/V₁ = 2 moles* 8.314 J/mol K* 300K / 0.1 m3= 49884 Pa
since P₂ = 1 atm = 101325 Pa
W= n*R*T * ln (P₁/P₂ ) = 2 mol * 8.314 J/mol K * 300K * (49884 Pa/101325 Pa) = -3534.94 J