Answer:
Work done required is 3567.2 J
Explanation:
Given :
Length of chain, l = 72 m
Mass of chain, M = 29 kg
Linear mass density of chain, μ = 
= 
= 0.40 kg/m
Let x be the length of the chain which lift to the top of the building.
Work done required to lift the chain is equal to the potential energy of the chain.
W = ∫μg (72 - x ) dx
Here g is acceleration due to gravity.
The limit of integration is from 0 to 14.
W = μg ( 72x - x²/2)
Substitute 0.40 kg/m for μ, 9.8 m/s² for g and 14 m for x in the above equation.
W = 
W = 3567.2 J
I'll assume that the chair has four legs.
Since the chair weights 3.7 kg by itself, it will weigh (79+3.7)=82.7 kg with the person sitting on it. And each of the chair's legs will take about (82.7/4)=20.675 kg.
Each leg touches the floor in a circle with 1.3cm diameter. The area of that circle is about (3.14*(1.3/2)^2)=1.327 cm^2.
Pressure is measured by force per area. So, the pressure from each leg is about 20.675kg / 1.327cm^2. That simplifies to 15.58 kg/cm^2.
Answer:
O ksm/s
Explanation:
before collision,
Velocity =0
So,momentum of the bottle before collision=mass ×velocity
=mass×0
=0 kgm/s
Answer is 3. Volume= mass divided by density
Answer:
A)s = 104.16 m
b)s= 104.16 m
Explanation:
Given that
u = 25 m/s
μ = 0.3
The friction force will act opposite to the direction of motion.
Fr= μ m g
Fr= - m a
a=acceleration
μ m g = - m a
a= - μ g
a= - 0.3 x 10 m/s² ( take g= 10 m/s²)
a= - 3 m/s²
The final speed of the mass is zero ,v= 0
We know that
v² = u² +2 a s
s=distance
0² = 25² - 2 x 3 x s
625 = 6 s
s = 104.16 m
By using energy conservation
Work done by all the forces =Change in the kinetic energy
Negative sign because force act opposite to the displacement.
- 3 x 2 x s = - 625
s= 104.16 m
