# SC PHYS 201 - Exam 3 Study Guide (6 pages)

Previewing pages*1, 2*of 6 page document

**View the full content.**## Exam 3 Study Guide

Previewing pages *1, 2*
of
actual document.

**View the full content.**View Full Document

## Exam 3 Study Guide

0 0 249 views

- Pages:
- 6
- Type:
- Study Guide
- School:
- University Of South Carolina-Columbia
- Course:
- Phys 201 - General Physics I
- Edition:
- 1

**Unformatted text preview: **

Phys 201 1st Edition Exam 3 Study Guide Lectures 15 20 Lecture 15 October 27 A 70kg soccer player kicks a 5kg ball giving it a speed of 14m s The contact time of the foot on the ball is 0 1s a What is the force on the ball b What is the force on the foot Answer a 70N b 70N Explaination a Kicking the ball changes the balls momentum Therefore we can use the momentum equation to solve for the force F t f i mVf mVi 14 5 0 7 F t F t 7kgm s F 7 t 7 1 70N b There is no need to calculate the force on the foot Consider Newton s third law For every action there is an equal and opposite reaction This means that the force on the foot will be the same as the force on the foot just in the opposite direction Lecture 15 October 27 A 1668 0 g mass is on a horizontal surface with k 0 37 and is in contact with a massless spring with a force constant of 619 0 N m which is compressed When the spring is released it does 2 51 J of work on the mass while returning to its equilibrium position a Calculate the distance the spring was compressed b What is the velocity of the mass as it loses contact with the spring Answer a 09 m b 1 534 m s Explanation a PEspring 5kx2 2 51 5 619 x2 X2 0081 X 09 b The easiest was to calculate the velocity of the mass is from its kinetic energy which is equal to the work done by the compressed minus the work done by friction The work done by friction is equal to the force of friction times the distance that the spring was compressed KE Ws Wf 5mV2 Ws fx F 37 1 668 9 81 F 6 04N 5 1 668 V2 2 51 6 04 09 V2 2 3758 V 1 535 Lecture 16 October 29 A croquet mallet delivers an impulse of 8 77 N s to a 0 64 kg croquet ball initially at rest What is the speed of the ball immediately after being struck Answer 13 7m s Explanation Impulse p Ft p mV 8 77 64 V V 13 7m s Lecture 16 October 29 A 0 145 kg baseball traveling 33 50 m s is stopped in 0 193 s by a catcher s mitt A What is the average acceleration of the ball b What is the average force on the catcher s mitt Answer a

View Full Document