Answer:
K.E = 30,000 J
Explanation:
Given,
The potential energy of the roller coaster car, P.E = 40000 J
The kinetic energy at height h/4, K.E = ?
According to the law of conservation of energy, the total energy of the system is conserved.
At height 'h', the total energy is,
P.E = mgh
K.E = 0
At height 'h/4', the total energy is
P.E + K.E = mgh
P.E = mgh/4
K.E = 1/2 mv²
Therefore,
mgh/4 + 1/2 mv² = mgh
gh/4 + v²/2 = gh
Hence,
v² = 3gh/2
Substituting in the K.E equation
K.E = 1/2 mv²
= 1/2 m (3gh/2)
= 3/4 mgh
= 3/4 x 40000
= 30000 J
Hence, the K.E of the roller coaster car is, K.E = 30000 J
Answer:
1.33
Explanation:
speed of light in vacuum, c = 3 x 10^8 m/s
speed of light in medium, v = 2.26 x 10^8 m/s
The refractive index of the medium is given by
μ = speed of light in vacuum / speed of light in medium
μ = (3 x 10^8) / (2.26 x 10^8)
μ = 1.33
Answer:
128805.2988 cm squared or 128000 to 3 significant figures.
Explanation:
Area of a circle : pi times radius squared or 
pi times 4.1×10^4 cm = 41000 pi or 128805.2988
Answer:
16.45 m/s
Explanation:
Let y be the vertical distance and x be the horizontal distance
We are given that
The altitude of hang glider increasing at the rate=
The shadow of the glider moves along the ground at speed=
We have to find the magnitude of glider's velocity.
We know that
Magnitude of velocity=
Substitute the values



Hence, the magnitude of glider's velocity=16.45 m/s
KE = 1/2 * m* v^2
= 1/2 * 40 * 225
= 4500 J
hope it helped