Answer:
The time taken for the ball to fly up in the air and back down again is 3.058 seconds.
Explanation:
Since the ball ends up at the same vertical distance ( on the ground) as it was at the start of its motion, we can set the total displacement of the ball equal to 0.
Thus, this problem can be simply solved by the following equation of motion:
Here, s = total change in distance = 0 m
u = initial speed = 15 m/s
a = acceleration due to gravity = -9.81 m/s^2
t = time (to be found)
Substituting these values in the equation we get:
t = 3.058 seconds
So, the time taken for the ball to fly up in the air and back down again is 3.058 seconds.
Answer:
A
A. Energy is lost when machines don't work right.
Answer:
energy from excess mass
Explanation:
The correct answer for the given question out of the given options is the option " energy from excess mass ".
This happens due to the fact that some of the matter is converted into the energy during the fusion of atoms.
The relation that can be stated is E = mc²
where,
E is the energy
c is the speed of the light
m is the mass of the matter
Answer:
R₁ = 0.126 m
Explanation:
Let's use the definition of intensity which is the power per unit area
I = P / A
the generated power is constant
P = I A
power is
P = E / t
if we perform the calculations for a given time, the wave energy is
E = q V
we substitute
P = 
we can write this equation for two points, point 1 the antenna and point 2 the receiver
V₁A₁ = V₂A₂
A₁ = 
A₁ = 0.1 10⁻³ 5 10⁻⁴ /V₁
A₁ = 5 10⁻⁸ /V₁
In general, the electric field on the antenna is very small on the order of micro volts, suppose V₁ = 1 10⁻⁶ V
let's calculate
A₁ = 5 10⁻⁸ / 1 10⁻⁶
A₁ = 5 10⁻² m²
the area of a circle is
A = π r²
we substitute
π R1₁²= 5 10⁻²
R₁ = 
R₁ = 0.126 m
Answer:
825 kgm⁻³
Explanation:
ρ = density of wood = ?
ρ' = density of water = 1000 kgm⁻³
V = volume of wood = 10 x 4 x 2 = 80 cm³ = 80 x 10⁻⁶ m³
V' = Volume of water displaced = 10 x 4 x 1.65 = 66 cm³ = 66 x 10⁻⁶ m³
Using equilibrium of force in vertical direction
Force of buoyancy = Weight of the wood
ρ' V' g = ρ V g
ρ' V' = ρ V
(1000) (66 x 10⁻⁶) = ρ (80 x 10⁻⁶)
ρ = 825 kgm⁻³
