7. A 2-kg mortar shell in a fireworks display rises from the ground to a height at which it is moving directly upward at 10 m/s. At this instant, the shell explodes and splits into two pieces. A 0.5-kg heads off northward and exactly horizontally at a speed of 20 m/s. What is the velocity (magnitude and direction) of the second piece? What is the change in kinetic energy during the explosion?

7. A 2-kg mortar shell in a fireworks display rises from the ground to a height at which it is moving directly upward at 10 m/s. At this instant, the shell explodes and splits into two pieces. A 0.5-kg heads off northward and exactly horizontally at a speed of 20 m/s. What is the velocity (magnitude and direction) of the second piece? What is the change in kinetic energy during the explosion?

Physics for Scientists and Engineers, Technology Update (No access codes included)

9th Edition

ISBN:9781305116399

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter8: Conservation Of Energy

Section: Chapter Questions

Problem 8.7P: Two objects are connected by a light string passing over a light, frictionless pulley as shown in...

See similar textbooks

Similar questions

You hold a slingshot at arms length, pull the light elastic band back to your chin, and release it to launch a pebble horizontally with speed 200 cm/s. With the same procedure, you fire a bean with speed 600 cm/s. What is the ratio of the mass of the bean to the mass of the pebble? (a) 19 (b) 13 (c) 1 (d) 3 (e) 9
A tennis player receives a shot with the ball (0.060 0 kg) traveling horizontally at 50.0 m/s and returns the shot with the ball traveling horizontally at 40.0 m/s in the opposite direction. (a) What is the impulse delivered to the ball by the tennis racquet? (b) What work does the racquet do on the ball?
A tennis ball of mass 57.0 g is held just above a basketball of mass 590 g. With their centers vertically aligned, both balls are released from rest at the same time, falling through a distance of 1.20 m, as shown in Figure P6.45. (a) Find the magnitude of the basketballs velocity the instant before the basketball reaches the ground. (b) Assume that an elastic collision with the ground instantaneously reverses the velocity of the basketball so that it collides with the tennis ball just above it. To what height does the tennis ball rebound? Figure P6.45
Three runaway train cars are moving on a frictionless, horizontal track in a railroad yard as shown in Figure P11.73. The first car, with mass m1 = 1.50 103 kg, is moving to the right with speed v1 = 10.0 m /s; the second car, with mass m2 = 2.50 103 kg, is moving to the left with speed v2 = 5.00 m/s, and the third car, with mass m3 = 1.20 103 kg, is moving to the left with speed v3 = 8.00 m /s. The three railroad cars collide at the same instant and couple, forming a train of three cars. a. What is the final velocity of the train cars immediately after the collision? b. Would the answer to part (a) change if the three cars did not collide at the same instant? Explain. FIGURE P11.73
A mother pushes her son in a stroller at a constant speed of 1.52 m/s. The boy tosses a 56.7-g tennis ball straight up at 1.75 m/s and catches it. The boys father sits on a bench and watches. a. According to the mother, what are the balls initial and final momenta? b. According to the father, what are the balls initial and final momenta? c. According to the mother, is the balls momentum ever zero? If so, when? If not, why not? d. According to the father, is the balls momentum ever zero? If so, when? If not, why not?
The coefficient of friction between the block of mass ml = 3.00 kg and the surface in Figure P7.22 is k = 0.400. The system starts from rest. What is the speed of the ball of mass, m2 = 5.00 kg when it has fallen a distance h = 1.50 m? Figure P7.22
In a “Top Fail” video (https://openstaxcollege.org/l/21topfailvideo), two women run at each other and collide by hitting exercise balls together. If each woman has a mass of 50 kg, which includes the exercise ball, and one woman runs to the right at 2.0 m/s and the other is running toward her at 1.0 m/s, (a) how much total kinetic energy is there in the system? (b) If energy is conserved after the collision and each exercise ball has a mass of 2.0 kg, how fast would the balls fly off toward the camera?
A car crashes into a large tree that does not move. The car goes from 30 m/s to 0 in 1.3 m. (a) What impulse is applied to the driver by the seatbelt, assuming he follows the same motion as the car? (b) What is the average force applied to the driver by the seatbelt?
An object that has a small mass and an object that has a large mass have the same momentum. Which object has the largest kinetic energy?
Sand from a stationary hopper falls onto a moving conveyor belt at the rate of 5.00 kg/s as shown in Figure P8.64. The conveyor belt is supported by frictionless rollers and moves at a constant speed of v = 0.750 m/s under the action of a constant horizontal external force Fext supplied by the motor that drives the belt. Find (a) the sands rate of change of momentum in the horizontal direction, (b) the force of friction exerted by the belt on the sand, (c) the external force Fext, (d) the work done by Fext in 1 s, and (e) the kinetic energy acquired by the falling sand each second due to the change in its horizontal motion. (f) Why are the answers to parts (d) and (e) different? Figure P8.64
(a) Figure P9.36 shows three points in the operation of the ballistic pendulum discussed in Example 9.6 (and shown in Fig. 9.10b). The projectile approaches the pendulum in Figure P9.36a. Figure P9.36b shows the situation just after the projectile is captured in the pendulum. In Figure P9.36c, the pendulum arm has swung upward and come to rest momentarily at a height A above its initial position. Prove that the ratio of the kinetic energy of the projectilependulum system immediately after the collision to the kinetic energy immediately before is m1|/(m1 + m2). (b) What is the ratio of the momentum of the system immediately after the collision to the momentum immediately before? (c) A student believes that such a large decrease in mechanical energy must be accompanied by at least a small decrease in momentum. How would you convince this student of the truth? Figure P9.36 Problem. 36 and 43. (a) A metal ball moves toward the pendulum. (b) The ball is captured by the pendulum. (c) The ballpendulum combination swings up through a height h before coming to rest.
A car of mass m moving at a speed v1 collides and couples with the back of a truck of mass 2m moving initially in the same direction as the car at a lower speed v2. (a) What is the speed Vf of the two vehicles immediately after the collision? (b) What is the change in kinetic energy of the car-truck system in the collision?