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Repeat Exercise 5.18 with the contestant pulling the block of ice with a rope over his shoulder at the same angle above the horizontal as shown in Figure 5.21 (b).

Exercise 5.18

A contestant in a winter sporting event pushes a 45.0-kg block of ice across a frozen lake as shown in Figure 5.21(a). (a) Calculate the minimum force $F$ he must exert to get the block moving. (b) What is the magnitude of its acceleration once it starts to move, if that force is maintained?
Question Image
<b>Figure 5.21</b> A person sliding a block of ice on a frozen lake. (a) by pushing, (b) by pulling on a rope inclined above the horizontal.
Figure 5.21 A person sliding a block of ice on a frozen lake. (a) by pushing, (b) by pulling on a rope inclined above the horizontal.
Question by OpenStax is licensed under CC BY 4.0.

a) $46.5 \textrm{ N}$

b) $0.656 \textrm{ m/s}^2$

Solution Video

OpenStax College Physics Solution, Chapter 5, Problem 19 (Problems & Exercises) (6:48)

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3 votes with an average rating of 3.7.

Calculator Screenshots

OpenStax College Physics, Chapter 5, Problem 19 (PE) calculator screenshot 1

Comments

Submitted by MEllis20 on Thu, 05/14/2020 - 01:06

This answer is incorrect. a) 51.04 and b) 0.719

Submitted by ShaunDychko on Sat, 05/16/2020 - 16:50

Hi MEllis20, thanks for the comment. I appreciate students keeping an eye out for mistakes. The answers you've given are for problem 18 where the person pushes at an angle below the horizontal, as in part (a) of the figure. In this problem (#19), the person pulls at an angle above the horizontal using a rope as in part (b) in the figure, and the force required is less than in problem 18, as expected since there is less normal force and thus less friction.
All the best,
Shaun

In reply to by MEllis20

Submitted by brittanyrio on Thu, 05/28/2020 - 13:32

I am having some trouble with the audio skipping in this video, along with some others.

Submitted by ShaunDychko on Thu, 05/28/2020 - 14:57

Hello brittanyrio, thank you very much for reporting this. I gave this video a listen and didn't notice a problem from this end. Is there a particular time in the video when you notice this? Does it make a difference if you use a different web browser? I'm always interested in issues students might have with playback since I wouldn't know there's a problem unless someone reports it, so thank you again.

In reply to by brittanyrio