Answer:

Given:
Radius of curvature (R) of a spherical mirror = 20
To Find:
Focal length (f)
Explanation:
Formula:

Substituting value of R in the equation:



Simply, apply the formula

and insert the values of m = mass, v = velocity and E = Energy.
The result will be

, m = 1 kg
Answer:
Dimension of cardboard is 22 m by 16 m
Explanation:
Given that,
Area = 352 cm²
Side of each square cutting from corner = 2 cm
Volume of box = 432 cm³
Let the two sides are x and y.
The area of the rectangular piece is

-------- (1)
The volume of the rectangular piece



x=16,22
Put the value of x in the equation (I)
For x = 16
For x = 22
Dimension of cardboard is 22 m by 16 m
Answer:
wallah i don't understand anything with my stoopid brain
Explanation:
Answer:
a) -41.1 Joule
b) 108.38 Kelvin
Explanation:
Pressure = P = 290 Pa
Initial volume of gas = V₁ = 0.62 m³
Final volume of gas = V₂ = 0.21 m³
Initial temperature of gas = T₁ = 320 K
Heat loss = Q = -160 J
Work done = PΔV
⇒Work done = 290×(0.21-0.62)
⇒Work done = -118.9 J
a) Change in internal energy = Heat - Work
ΔU = -160 -(-118.9)
⇒ΔU = -41.1 J
∴ Change in internal energy is -41.1 J
b) V₁/V₂ = T₁/T₂
⇒T₂ = T₁V₂/V₁
⇒T₂ = 320×0.21/0.62
⇒T₂ = 108.38 K
∴ Final temperature of the gas is 108.38 Kelvin