Concept explainers
(a)
Distance required to bring the car to a stop when the car is skidding.
(a)
Answer to Problem 46P
The distance is
Explanation of Solution
According to Newton’s laws
Here
The acceleration is in the opposite direction from the velocity, and so has a negative sign.
Then the distance travelled is,
Here
Conclusion:
Substitute
The distance is
(b)
Distance required to bring the car to a stop when the wheels are not locked up.
(b)
Answer to Problem 46P
The distance is
Explanation of Solution
In the case of non-skidding, the distance covered would be
Here
Conclusion:
Substitute
The distance is
(c)
The distance the wheels go if the wheels lock into a skidding stop.
(c)
Answer to Problem 46P
The distance is
Explanation of Solution
The skidding car goes by
Or,
The ratio implies that at any speed, the skidding car will have
The stopping distance with antilock brakes is shorter.
Conclusion:
The distance is
(d)
Whether antilock brake makes big difference in emergency stops.
(d)
Answer to Problem 46P
The stopping distance of cars with antilock brakes are significantly shorter around
Explanation of Solution
Antilock brakes generally offers improved vehicle control and decreases stopping distances on dry and some slippery surfaces, on loose gravel or snow-covered surfaces. They significantly decrease braking distance, while still improving steering control.
Conclusion:
Therefore, the stopping distance of cars with antilock brakes are significantly shorter around
Want to see more full solutions like this?
Chapter 3 Solutions
Bundle: College Physics: Reasoning And Relationships, 2nd + Webassign Printed Access Card For Giordano's College Physics, Volume 1, 2nd Edition, Multi-term
- Which of the following is impossible for a car moving in a circular path? Assume that the car is never at rest. (a) The car has tangential acceleration but no centripetal acceleration. (b) The car has centripetal acceleration but no tangential acceleration. (c) The car has both centripetal acceleration and tangential acceleration.arrow_forwardAs their booster rockets separate, Space Shuttle astronauts typically feel accelerations up to 3g, where g = 9.80 m/s2. In their training, astronauts ride in a device where they experience such an acceleration as a centripetal acceleration. Specifically, the astronaut is fastened securely at the end of a mechanical arm, which then turns at constant speed in a horizontal circle. Determine the rotation rate, in revolutions per second, required to give an astronaut a centripetal acceleration of 3.00g while in circular motion with radius 9.45 m.arrow_forward0-2. An automobile drag racer drives a car with acceleration a and instantaneous veloc- ity v. The tires (of radius r) are not slipping. Find which point on the tire has the greatest acceleration relative to the ground. What is this acceleration?arrow_forward
- Suppose a car is moving along a flat piece of road. Moreover, let us suppose that we know the coefficient of friction within the axles and wheel bearings of the car to be ?=0.015μ=0.015 . If the car let's off the accelerator (gas pedal) and starts rolling, and you measure that it takes the car 800 meters to roll to a stop (without using the breaks), how fast was the car moving the moment the driver removed her/his foot from the pedal? Give your answer in units of m/s, however do not include the units explicitly in your answer. If you include units, the answer will be counted wrong.arrow_forward8. A traditional watch has a second hand 1.5 cm long, from centre to tip. (a) What is the speed of the tip of the second hand? (b) What is the velocity of the tip at 15 s? at 45 s? at 60 s? (c) What is its change in velocity between 30 s and 45 s? (d) What is its average acceleration during the same interval?arrow_forwardTo withstand “g-forces” of up to 10 g’s, caused by suddenly pulling out of a steep dive, fighter jet pilots train on a “human centrifuge.” 10 g’s is an acceleration of 98 m/s2. If the length of the centrifuge arm is 12 m, at what speed is the rider moving when she experiences 10 g’s?arrow_forward
- A marble rolls down an incline at 25° from rest. (a) What is its acceleration (in m/s2)? (Enter the magnitude.) m/s2 (b) How far (in m) does it go in 4.8 s? marrow_forwardEx. 64: A car can be driven on a flat circular road of radius r at a maximum speed v without skidding. The same car is now driven on another flat circular road of radius 2r on which the coefficient of friction between the tyres and the road is the same as on the first road. What is the maximum speed of the car on the second road such that it does not skid ?arrow_forwardAt its Ames Research Center, NASA uses its large “20 G” centrifuge to test the effects of very large accelerations (“hypergravity”) on test pilots and astronauts. In this device, an arm 8.84 m long rotates about one end in a horizontal plane, and an astronaut is strapped in at the other end. Suppose that he is aligned along the centrifuge’s arm with his head at the outermost end. The maximum sustained acceleration to which humans are subjected in this device is typically 12.5g. (a) How fast must the astronaut’s head be moving to experience this maximum acceleration? (b) What is the difference between the acceleration of his head and feet if the astronaut is 2.00 m tall? (c) How fast in rpm 1rev>min2 is the arm turning to produce the maximum sustained acceleration?arrow_forward
- A sprinter practicing for the 200-m dash accelerates uniformly from rest at A and reaches a top speed of 37 km/h at the 52-m mark. He then maintains this speed for the next 97 meters before uniformly slowing to a final speed of 31 km/h at the finish line. Determine the maximum horizontal acceleration which the sprinter experiences during the run. Where does this maximum acceleration value occur? Part 1 Answers: Calculate (a) the magnitude of the tangential acceleration near start of the race and (b) the magnitude of the tangential acceleration near the end of the race. (a) |at| = (b) |at| = i Finish line i m/s² 39.9 m m/s²arrow_forwardOur balance is maintained, at least in part, by the endolymph fluid in the inner ear. Spinning displaces this fluid, causing dizziness. Suppose that a skater is spinning very fast at 3.0 revolutions per second about a vertical axis through the center of his head. Take the inner ear to be approximately 7.0 cm from the axis of spin. (The distance varies from person to person.) What is the radial acceleration (in m>s 2 and in g’s) of the endolymph fluid?arrow_forward(5) In 1992, a 14 kg meteorite struck a car in Peekskill, NY, leaving a 20-cm-deep dent in the trunk. (a) If the meteorite was moving at 500 m/s before striking the car, what was the magnitude of its acceleration while stopping? Indicate any assumptions you made. (b) What other questions can you answer using the data in the problem?arrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning