Answer:
Option C
100 J
Explanation:
Kinetic energy, KE is given by
where m is the mass and v is the velocity
Substituting 50 Kg for mass, m and 2 m/s for velocity v then we obtain

Therefore, the child's kinetic energy is equivalent to 100 J
Given that,
Time = 0.5 s
Acceleration = 10 m/s²
(I). We need to calculate the speed of apple
Using equation of motion

Where, v = speed
u = initial speed
a = acceleration
t = time
Put the value into the formula


(III). We need to calculate the height of the branch of the tree from the ground
Using equation of motion

Put the value into the formula


(II). We need to calculate the average velocity during 0.5 sec
Using formula of average velocity


Where,
= final position
= initial position
Put the value into the formula


Hence, (I). The speed of apple is 5 m/s.
(II). The average velocity during 0.5 sec is 2.5 m/s
(III). The height of the branch of the tree from the ground is 1.25 m.
Answer:
Y component = 32.37
Explanation:
Given:
Angle of projection of the rocket is, 
Initial velocity of the rocket is, 
A vector at an angle
with the horizontal can be resolved into mutually perpendicular components; one along the horizontal direction and the other along the vertical direction.
If a vector 'A' makes angle
with the horizontal, then the horizontal and vertical components are given as:

Here, as the velocity is a vector quantity and makes an angle of 33.6 with the horizontal, its Y component is given as:

Plug in the given values and solve for
. This gives,

Therefore, the Y component of initial velocity is 32.37.
Principle: Pythagorean theorem
Given:
Let a = boat velocity = 25 miles per hour
b = river velocity = 10 miles per hour
Required: c = actual velocity
Solution:
c^2 = a^2 + b^2
c^2 = (25)^2 + (10)^2
c^2 = 725
(c^2)^0.5 = (725)^0.5
c = 26.93 miles per hour
<em>ANSWER: Actual boat velocity is 26.93 miles per hour</em>
Answer:
I = 9.82 10⁻⁷ W / m²
Explanation:
The intensity of the sound wave is the energy of the wave between the order per unit area of the same
I = P / A = E / T A
the energy is calculated by integrating the mechanical energy in a period, where the mass is changed by the density and ‘s’ is the amplitude of the sound wave
I = ½ ρ v (w s)²
I = ½ 1.35 328 (2π 530 2.00 10⁻⁸)²
I = 221.4 (4.435 10⁻⁹)
I = 9.82 10⁻⁷ W / m²