Aski that is placed on snow will stick to the snow. however, when the ski is moved along the snow, the rubbing warms and partially melts the snow, reducing the coefficient of friction and promoting sliding. waxing the ski makes it water repellent and reduces friction with the resulting layer of water. a magazine reports that a new type of plastic ski is especially water repellent and that, on a gentle 200 m slope in the alps, a skier reduced his top-to-bottom time from 47.94 s with standard skis to 33.94 s with the new skis. determine the magnitudes of his average acceleration with each pair of skis. acceleration with old model ski? acceleration with new model ski? assuming a 4.0° slope, compute the coefficient of kinetic friction for each case. old model ski coefficient of friction? new model ski coefficient of friction?

a). Acceleration with old model

b). Acceleration with new model

c). Coefficient of kinetic friction old model

d). Coefficient of kinetic friction old model

Explanation:

Using the Newton laws so the initial speed is zero

so:

Δ

because the ski began from the rest initial velocity is zero

Δ

a).

b).

In the horizontal direction the friction force acts on the ski is:

c).

d).

explanation:

earth's surface is mainly heated by the absorption of infrared radiation from the sun.

evaporation occurs because molecules in liquid water are warmed ( usually by the sun) and vibrate quicker, becoming less dense and rise.

condensation occurs because molecules in water vapor are cooled and therefore vibrate more slowly thus becoming more dense and eventually fall to earth.

lines of equal barometric pressure on a weather map are called: isobars : lines of equal temp on a weather map are called: isotherms.​

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: