Answer:
Explanation:
a )
one kg of coal gives energy of 27 x 10⁶ J
75 kg of coal gives energy of 27 x 10⁶ x 75 J
So rate which energy is coming out of coal per second
= 27 x 10⁶ x 75 J
= 2025 x 10⁶ J /s
2025 million watts .
b ) energy output = 800 million watts
efficiency = (800 / 2025) x 100
= 39.5 % .
Answer:
man upward acceleration is 0.14m/s^2
Explanation:
given data:
mass of man = 72 kg
downward force = 360 N
The mass of man of weight 72 kg is hang from two sections of rope, one section pf rope ties around man waist and other section is ties in man hands. when he pulls down the rope with 360 N force then each section of rope pulls with 360 N
we know that
Weight= mass × gravity= 72kg × 9.8 = 705.6N
Force = mass× acceleration
Force= -705.6 + (2 × 358) = 10.4 N

Answer:
8.67807 N
34.7123 N
Explanation:
m = Mass of shark = 92 kg
= Density of seawater = 1030 kg/m³
= Density of freshwater = 1000 kg/m³
= Density of shark = 1040 kg/m³
g = Acceleration due to gravity = 9.81 m/s²
Net force on the fin is (seawater)

The lift force required in seawater is 8.67807 N
Net force on the fin is (freshwater)

The lift force required in a river is 34.7123 N
Answer:
There is 148.35 Joules of heat is released in the process.
Explanation:
Given that,
Heat capacity of the object, 
Initial temperature, 
Final temperature, 
We need to find the amount of heat released in the process. It is a concept of heat capacity. The heat released in the process is given by :

Let the mass of the object is 10 g or 0.01 kg
So,

Q = 148.35 Joules
So, there is 148.35 Joules of heat is released in the process. Hence, this is the required solution.
Answer:
the correct answer is c v₁> 12.5 m / s
Explanation:
This is a one-dimensional kinematics exercise, let's start by finding the link to get up to speed.
v² = v₀² + 2 a₁ x
as part of rest v₀ = 0
a₁ = v² / 2x
a₁ = 25² / (2 120)
a₁ = 2.6 m / s²
now we can find the velocity for the distance x₂ = 60 m
v₁² = 0 + 2 a1 x₂
v₁ = Ra (2 2,6 60)
v₁ = 17.7 m / s
these the speed at 60 m
we see that the correct answer is c v₁> 12.5 m / s