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1.) Two blocks are at rest on a horizontal friction-less surface with a compress

ID: 1313703 • Letter: 1

Question

1.) Two blocks are at rest on a horizontal friction-less surface with a compressed spring between them. The 10-kg block accelerates when the string holding the system in compression is cut and the 20-kg box accelerates in the opposite direction. What is the magnitude of the force from the expanding spring on the 20-kg box when the 10-kg box is undergoing an acceleration of 8.0 ?

a. 160 N

b. 80 N

c. 42.4 N

d. 40 N

2.) A particle moves east at constant velocity (of magnitude = v) for a time interval T. It then moves north at a constant velocity, with the same speed as before, for another time interval T. Finally it moves wast at a constant velocity with the same speed as before for another time interval T. Which of the following are true about the magnitude and direction of the average velocity for the motion described?

a. v/3, north

b. 3v, nort

c. zero

d. 1.4 v, northeast

Explanation / Answer

a. it will 8*10=80 N

spring will equal and oppsiite in direction

2. a.