# Review: Friction and M/s

Topics: Friction, Classical mechanics, Automobile Pages: 2 (532 words) Published: May 11, 2013
Review MCQ’s Chapter Six [Work-Energy] Physics I Spring 2013 1-A 10.0-g bullet traveling horizontally at 755 m/s strikes a stationary target and stops after penetrating 14.5 cm into the target. What is the average force of the target on the bullet? A)-1.97 × 104 N B)-2.07 × 105 N C)-6.26 × 103 N D)-3.13 × 104 N E)-3.93 × 104 N 2-A car is traveling at 7.0 m/s when the driver applies the brakes. The car moves 1.5 m before it comes to a complete stop. If the car had been moving at 14 m/s, how far would it have continued to move after the brakes were applied? Assume the braking force in both cases is constant and the same. A)-1.5 m B)-3.0 m C)-4.5 m D)-6.0 m E)-7.5 m 3-An automobile approaches a barrier at a speed of 20 m/s along a level road. The driver locks the brakes at a distance of 50 m from the barrier. What minimum coefficient of kinetic friction is required to stop the automobile before it hits the barrier? A)-0.4 B)-0.5 C)-0.6 D)-0.7 E)-0.8 4-How much power is needed to lift a 75-kg student vertically upward at a constant speed of 0.33 m/s? A)-12.5 W B)-25 W C)-115 W D)-230 W E)-243 W 5-A motorist driving a 1000-kg car wishes to increase her speed from 20 m/s to 30 m/s in 5 s. Determine the horsepower required to accomplish this increase. Neglect friction. A)-20 hp B)-30 hp C)-70 hp D)-80 hp E)-90 hp

PDF created with pdfFactory Pro trial version www.pdffactory.com

6-A 325-N force accelerates a 50.0-kg crate from rest along a horizontal frictionless surface for a distance of 20.0 m as shown in the figure. What is the final speed of the crate?

A)-11.4 m/s B)-16.1 m/s C)-32.2 m/s D)-131 m/s E)-259 m/s 7-A 325-N force accelerates a 50.0-kg crate from rest along a horizontal frictionless surface for a distance of 20.0 m as shown in the figure. What coefficient of friction would be required to keep the crate moving at constant speed under the action of the 325-N force?

A)-0.250 B)-0.321 C)-0.508 D)-0.663 E)-0.747 8-Use the work-energy theorem to find...