Question

On their way home from the amusement park, the girl's mom is driving their 1250 kg car around afloat curve of radius 65.0 m. Alight rain has started, and the coefficient of friction ps between the tires and the road surface has dropped to 0.75. If her mom is driving at 45 mi/hr (which is 20.1 m/s) will the car stay on the road, or will it slide off? Yes, the car will stay on the road, because the safe speed to make the curve is 35.0 m/s. Yes, the car will stay on the road, but just barely, because the safe speed is 21.9 m/s. Oh no! The car will slide off, because the safe speed to make the curve is 18.7 m/s. Mom! Pay attention! The car will slide off because the safe speed is only 8.7 m/s. When a 8.00 kg mass is placed on top of a vertical spring, the spring compresses 4.28 cm, the force constant of spring equal to 1832 N/m 1.862 N/m 50 N/m 85 N/m

Answer 1

here,

radius , r = 65 m

us = 0.75

speed of car , v = 20.1 m/s

centripital force , fc = m* v^2 /r = 1250 * 20.1^2 /65 = 7769.4 m/s^2

the frictional force , ff = uk * m * g

ff = 0.75 * 1250 * 9.8 = 9187.5 N

as ff > fc

the car will stay on the road

for the safe speed

Fc = ff

m * u^2 /r = 9187.5

1250 * u^2 /65 = 9187.5

u = 21.9 m/s

so,

the correct option is B)

9)

mass , m = 8 kg

x = 4.28 cm = 0.0428 m

the force constant of spring , k = F/x

k = m * g /x = 9.8 * 8 /0.0428 N/m

k = 1832 N/m

the spring constant is A) 1832 N/m