At A, coaster is only associated with potential energy.
At B, coaster is associated with kinetic as well as potential energy.
Since the track is frictionless, no energy will be lost when coaster reaches from point A to point B. Therefore, according to conservation of energy, total energy at A should be equal to total energy at B.
Total energy at A = mgh = mg(12)
Total energy at B = mgh+ mv²/2 = mg(2) + mv²/2
∴12mg = 2mg + mv²/2
∴(12g-2g)×2 = v²
∴v² = 20g
∴v = 14m/s.
Again conserving energy at points B and C.
Total energy at B = 2mg + m(14)²/2
Total energy at C = 4mg + mv²/2
∴2mg + m(14²)/2 = 4mg + mv²/2
Solving this you get,
v = 12.52 m/s.
Therefore, speed of roller coaster at point C is 12.52 m/s.
Answer:
30 cm
Explanation:
f = Focal length = 25 cm
R = Radius of curvature (both sides are equal)
= Refractive index of lens = 1.6
The lens maker formula is given by
minus sign because it is on the other side

The radius of curvature of the glass surface is 30 cm
Answer:
The mass of the object on the Moon (and anywhere else) is about 30.61kg. Please see more detail below.
Explanation:
Weight is the gravitational force exerted on the object and is a function of mass and gravitational acceleration:
(weight) = (mass) x (gravitational acceleration)
We are to find the mass, knowing the weight on Earth to be 300N:
(mass) = (weight on Earth) / (gravitational acceleration on Earth) = 300N / 9.8 m/s^2 = 30.61 kg
The mass of the object is 30.61kg.
The mass of the object is independent of gravity. Therefore the answer to the question "What is its mass on the Moon" is 30.61kg.
If the question were what is its weight on the Moon, the answer would be
(weight on Moon) = (mass) x (grav.accel. on Moon) = 30.61kg x 1.62 m/s^2 = 49.59N
which is about 1/6 of the object's weight on the Earth.
Answer:
false
Explanation: all compounds are electrically neutral.