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Lecture 6 Discussion

Lecture 6 Discussion. [1] The position versus time for a certain particle moving along the x axis is shown in Figure. Find the average velocity in the time intervals

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Lecture 6 Discussion

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  1. Lecture 6 Discussion General Physics 1, Lec 6, By/T.A. Eleyan

  2. [1] The position versus time for a certain particle moving along the x axis is shown in Figure. Find the average velocity in the time intervals (a) 0 to 2 s, (b) 2 to 4 s, (c) 4 s to 5 s, (d) 4 s to 7 s, (e) 0 to 8 s. a) 0 to 2 s b) 2 to 4 s c) 4 to 5 s d) 4 to 7 s General Physics 1, Lec 6, By/T.A. Eleyan

  3. [2] A position-time graph for a particle moving along the x axis is shown in Figure • Find the average velocity in the time interval t = 1.5 s to t = 4 s. • At what value of t is the velocity zero? Solution: (a) (b) At time t = 4 sec General Physics 1, Lec 6, By/T.A. Eleyan

  4. [3] A particle moves along the x axis. Its position is given by the equation x= 2 t + 3t 2 with x in meters and t in seconds. Calculate the velocity andacceleration at t=3s. Solution: First, the instantaneous velocity at t=3s The instantaneous acceleration at t=3s General Physics 1, Lec 6, By/T.A. Eleyan

  5. [4] Consider the motion of the object whose velocity-time graph is given in the diagram 1- What is the acceleration of the object between times t=0 to 2s? 2- What is the acceleration of the object between times t=10 to 12s? 3- What is the net displacement of the object between times 0 to 16s? Solution: 1- 2- 3- equals the area under the v-t graph =100m2 how?the net displacement General Physics 1, Lec 6, By/T.A. Eleyan

  6. [5] A particle moves along the x axis according to the equation x = 2+ 3t - t 2 where , x is in meters and t is in seconds. At t= 3 s, find (a) the position of the particle, (b) its velocity, and (c) its acceleration. Solution: (a) the position of the particle (b) its velocity, (c) its acceleration General Physics 1, Lec 6, By/T.A. Eleyan

  7. [6] A truck covers 40m in 8.5 s while smoothly slowing down to a final speed of 2.80 m/s. (a) Find its original speed. (b) Find its acceleration. Solution: Let the origin be at the initial positionx0=0 (a) (b) General Physics 1, Lec 6, By/T.A. Eleyan

  8. [7] A boy throws a ball upward from the top of a building with an initial velocity of 20.0 m/s. The building is 50 meters high. Determine (a) the time needed for the ball to reach its maximum height (b) the maximum height (c) the time needed for the ball to reach the level of the thrower (d) the velocity of the stone at this instant (e) the velocity and position of the ball after 5.00 s (f) the velocity of the ball when it reaches the bottom of the building. Solution: Given Information: g = 9.8 m/s2 vo = 20 m/s yo= 50 m (a)  At maximum height v  = 0, so using General Physics 1, Lec 6, By/T.A. Eleyan

  9. (b) the maximum height (c) the time needed for the ball to reach the level of the thrower Note :the time to reach the top and back down to the thrower's level is the same so 2(2.04) = 4.08 seconds (d) the velocity of the ball at this instant Which is the same speed of the original throw upward, except now the negative implies that the ball is moving with a speed of 20 m/s downward. General Physics 1, Lec 6, By/T.A. Eleyan

  10. (e) the velocity and position of the ball after 5.00 s (f)  The velocity of the ball just at the moment it reaches the ground, But, the context of the problem would have us choose, -37.1 m/s because the ball is moving downward just as it hits the ground. General Physics 1, Lec 6, By/T.A. Eleyan

  11. [8]  Suppose a spacecraft is traveling with a speed of 3250 m/s, and it slows down by firing its retro rockets, so that a= -10 m/s2.  What is the velocity of the spacecraft after it has traveled 215km?  Solution: General Physics 1, Lec 6, By/T.A. Eleyan

  12. [9] A car can brake to a stop in a distance of 121 ft. from a speed of 60.0 mi/h. To brake to a stop from a speed of 80.0 mi/h requires a stopping distance of 211 ft. What is the average braking acceleration for (a) 60 mi/h to rest, (b) 80 mi/h to rest, (c) 80 mi/h to 60 mi/h? Express the answers m/s2. General Physics 1, Lec 6, By/T.A. Eleyan

  13. H.W General Physics 1, Lec 6, By/T.A. Eleyan

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