1.Car A is traveling at 77 km/h while car B is at 60 km/h. (a) What is the relat
ID: 2018244 • Letter: 1
Question
1.Car A is traveling at 77 km/h while car B is at 60 km/h.(a) What is the relative velocity of car A to car B if they both are traveling in the same direction?
km/h
(b) What is the relative velocity of car A to car B if they are headed towards each other?
km/h
2. A cross-country runner runs 2.5 km east along the course, then turns around and runs 2.5 km west along the same path. She returns to the starting point in 18 min. What is her average speed?
km/h
her average velocity?
km/h
3. A 0.24-kg volleyball approaches Jennifer with a velocity of 3.8 m/s. Jennifer bumps the ball giving it a velocity of -2.4 m/s. What average force did she apply if the interaction time between her hands and the ball is 0.025 s?
N
4. When a 21-kg child steps off a 3.5-kg stationary skateboard with an acceleration of 0.55 m/s2, with what acceleration will the skateboard travel in the opposite direction?
m/s2
Explanation / Answer
3. Given: mass of the volley ball m = 0.24 kg velocity v = 3.8 m/s time t f= 0.025 sec ........................................................................................ according to impulse-momentum theorem the impulse J applied to the ball is J = mvf-mvi = (0.24kg)(-2.4 m/s)-(0.24kg)(3.8m/s) = -0.336 kg.m/s momentum is a vector quantity and , as such , has a magnitude and a direction. now the average force F = J / t = -0.336 / 0.025 sec = -13.44 N The force is negative , indicating that it points towards the velocity of the approaching ball. NOTE:please should not post the multiple problems. post as seperate will be answered. Given: mass of the volley ball m = 0.24 kg velocity v = 3.8 m/s time t f= 0.025 sec ........................................................................................ according to impulse-momentum theorem the impulse J applied to the ball is J = mvf-mvi = (0.24kg)(-2.4 m/s)-(0.24kg)(3.8m/s) = -0.336 kg.m/s momentum is a vector quantity and , as such , has a magnitude and a direction. now the average force F = J / t = -0.336 / 0.025 sec = -13.44 N The force is negative , indicating that it points towards the velocity of the approaching ball. NOTE:please should not post the multiple problems. post as seperate will be answered. Given: mass of the volley ball m = 0.24 kg velocity v = 3.8 m/s time t f= 0.025 sec ........................................................................................ according to impulse-momentum theorem the impulse J applied to the ball is J = mvf-mvi = (0.24kg)(-2.4 m/s)-(0.24kg)(3.8m/s) = -0.336 kg.m/s momentum is a vector quantity and , as such , has a magnitude and a direction. now the average force F = J / t = -0.336 / 0.025 sec = -13.44 N The force is negative , indicating that it points towards the velocity of the approaching ball. NOTE:please should not post the multiple problems. post as seperate will be answered. = (0.24kg)(-2.4 m/s)-(0.24kg)(3.8m/s) = -0.336 kg.m/s momentum is a vector quantity and , as such , has a magnitude and a direction. now the average force F = J / t = -0.336 / 0.025 sec = -13.44 N The force is negative , indicating that it points towards the velocity of the approaching ball. NOTE:please should not post the multiple problems. post as seperate will be answered.Related Questions
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