In Fig. 8-18, a horizontally moving block can take three frictionless routes, differing only in elevation, to reach the dashed finish line. Rank the routes according to (a) the speed of the block at the finish line and (b) the travel time of the block to the finish line, greatest first. Figure 8-18 Question 1.
In Fig. 8-18, a horizontally moving block can take three frictionless routes, differing only in elevation, to reach the dashed finish line. Rank the routes according to (a) the speed of the block at the finish line and (b) the travel time of the block to the finish line, greatest first. Figure 8-18 Question 1.
In Fig. 8-18, a horizontally moving block can take three frictionless routes, differing only in elevation, to reach the dashed finish line. Rank the routes according to (a) the speed of the block at the finish line and (b) the travel time of the block to the finish line, greatest first.
Figure 8-18 Question 1.
Expert Solution & Answer
To determine
To find:
a) The ranking of routes according to the speed of the block at the finish line.
b) The ranking of routes according to the travel time of the block to the finish line, greatest first.
Answer to Problem 1Q
Solution:
a) The rank of routes according to the speed of the block at the finish line is 3,2,1.
b) The rank of routes according to travel time of the block to the finish line, greatest first, is 1,2,3.
Explanation of Solution
1) Concept:
We can rank the routes according to the speed of the block at the finish line by comparing the kinetic energy of the object along them. And from this rank, according to the definition of velocity, we can rank the routes according to travel time of the block to the finish line.
2) Formula:
i)
K.E.=12Mv2
ii)
Velocity,v=DT
3) Given:
i) A block moving horizontally along three frictionless routes.
4) Calculation:
a) For the object along the first route, it moves upward which is against the gravity, so gravity does work in the opposite direction on the object which reduces its kinetic energy. We know that
k.E=12Mv2
Therefore, its speed slows down.
Along the second route, the block moves without change in its speed.
For the block along the third route, it moves in the direction of gravity. So, gravity does work in the same direction on the object which reduces its kinetic energy.
Therefore, its speed increases.
Therefore, the ranking of routes according to the speed of the block at the finish line is 3,2,1.
b) We have,
v=DT
Therank of routes according to the speed of the block at the finish line is 3,2,1 and distance to travel is the same along all three routes.
As speed is less, the time taken to travel a certain distance is more.
Therefore, the rank of routes according to travel time of the block to the finish line, greatest first, is 1,2,3.
Conclusion:
We can rank the routes according to the speed and travelling time of an object by comparing kinetic energy of the object along them.
Want to see more full solutions like this?
Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Answer A and B for question 2
2. An object was a mass of 10.0 kg is at rest at the top of a frictionless inclined plane of length 8.00 m and an angle of inclination 30.0° with the horizontal. The object is released from this position and it stops at a distance d from the bottom of the inclined plane along a horizontal surface, as shown in Fig. 8-6. The coefficient of kinetic friction for the horizontal surface of 0.400.
(a) What is the speed of the object at the bottom of the inclined plane?
(b) At what horizontal distance from the bottom of the inclined plane will this object stop?
An Olympic swimmer stands on top of a platform at a height H above a swimming pool. At the moment of jumping into the pool, he jumps with a speed v_0 forming an angle θ with the horizontal, just as shown in the figure. The swimmer reaches a maximum height h measured from the platform to point B.
(d) If we assume that when entering the water the athlete follows a straight path traveling 3.50 m before coming to a complete stop in the water and that the frictional force exerted by the water is 206 N. Determine the change in mechanical energy that the athlete experiences when stopping in the water
A sledgehammer of mass m = 1.9 kg falls freely vertically downward from a height of h = 2.5 m at an initial speed of v = 6.5 m/s before striking a partially buried piling. After the blow the piling has moved d = 0.075 m deeper. How much force, in newtons, was applied to the piling? Assume all the energy goes towards driving the piling into the ground, and the force of the sledgehammer is constant over the distance d that the piling is driven into the ground. Note that you can ignore the change in potential energy of the piling itself. Further, because d is so small compared to h, you can also ignore the change in potential energy of the hammer as well as it moves distance d.
Chapter 8 Solutions
Fundamentals of Physics, Extended 10th Edition (WileyPLUS Access Code)
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.