You wish to make a simple amusement park ride in which a steel-wheeled roller-coaster car travels down one long slope, where rolling friction is negligible, and later slows to a stop through kinetic friction between the roller coaster's locked wheels sliding along a horizontal plastic (polystyrene) track. Assume the roller-coaster car (filled with passengers) has a mass of 743.0 kg and starts 83.4 m above the ground. (a) Calculate how fast the car is going when it reaches the bottom of the hill. m/s (b) How much does the thermal energy of the system change during the stopping motion of the car

(a) The car is going approximately 40.43 m/s at the bottom of the hill

(b) The thermal energy will increase by 607,268.76 J

Explanation:

In the question, we have;

The height of the roller coaster above ground = 83.4 m

The mass of the roller coaster, m = 743.0 kg

(a) By the conservation of energy principle, we have;

The potential energy at the top of the hill, P.E., is equal to the kinetic energy at the bottom of the hill, K.E.

∴ P.E. = K.E.

P.E. = m·g·h

Where;

m = The mass of the roller coaster = 743.0 kg

g = The acceleration due to gravity = 9.8 m/s²

h = The height of the roller coaster = 83.4 m

Therefore, we have;

P.E. = 743.0 kg × 9.8 m/s² × 83.4 m = 607,268.76 J

P.E. = 607,268.76 J

K.E. = 1/2·m·v²

∴ K.E. = 1/2 × 743.0 kg × v²

P.E. = K.E.

∴ P.E. = K.E. = 607,268.76 J

1/2 × 743.0 kg × v² = 607,268.76 J

v² = 607,268.76 J/(1/2 × 743.0 kg) = 1,634.64 m²/s²

v = √(1,634.64 m²/s²) ≈ 40.43 m/s

(b) Given that the material wheel moves along polystyrene track, the sound released will be minimal and almost all the kinetic energy will be converted to heat energy when the train stops, therefore, the thermal energy will increase by K.E. = 607,268.76 J

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

c) up is the direction the magnetic force is acting on the charge.