According to Eq. 7-4, the longer the impact time of an impulse, the smaller the force can be for the same momentum change, and hence the smaller the deformation of the object on which the force acts. On this basis, explain the value of air bags, which are intended to inflate during an automobile collision and reduce the possibility of fracture or death.
The quantity on the left, the product of the force
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Physics: Principles with Applications
- 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?arrow_forwardPendulum bob 1 has mass m1. It is displaced to height h1 and released. Pendulum bob 1 elastically collides with pendulum bob 2 of mass m2 (Fig. P11.43). FIGURE P11.43 a. Find an expression for the maximum height h2 of pendulum bob 2. b. If m2 = 2.5m1 and h1 = 5.46 m, what is h2?arrow_forwardA ball of mass 50.0 g is dropped from a height of 10.0 m. It rebounds after losing 75% of its kinetic energy during the collision process. If the collision with the ground took 0.010 s, find the magnitude of the impulse experienced by the ball.arrow_forward
- Two objects collide head-on (Fig. P11.39). The first object is moving with an initial speed of 8.00 m/s, and the second object is moving with an initial speed of 10.00 m/s. Assuming the collision is elastic, m1 = 5.15 kg, and m2 = 6.25 kg, determine the final velocity of each object. FIGURE P11.39arrow_forwardA tennis player receives a shot with the ball (0.060 0 kg) traveling horizontally at 20.0 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 racket? (b) Some work is done on the system of the ball and some energy appears in the ball as an increase in internal energy during the collision between the ball and the racket. What is the sum W Eint for the ball?arrow_forwardIn a laboratory experiment, an electron with a kinetic energy of 50.5 keV is shot toward another electron initially at rest (Fig. P11.50). (1 eV = 1.602 1019 J) The collision is elastic. The initially moving electron is deflected by the collision. a. Is it possible for the initially stationary electron to remain at rest after the collision? Explain. b. The initially moving electron is detected at an angle of 40.0 from its original path. What is the speed of each electron after the collision? FIGURE P11.50arrow_forward
- 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?arrow_forwardA bullet of mass m is fired into a ballistic pendulum and embeds itself in the wooden bob of mass M (Fig. P11.33). After the collision, the pendulum reaches a maximum height h above its original position. a. Show that the kinetic energy of the system decreases by the factor m/(m + M) immediately after the collision. b. What is the change in momentum of the bullet-bob system due to the collision? FIGURE P11.33arrow_forwardIn a laboratory, a cart collides with a wall and bounces back. Figure P11.10 shows a graph of the force exerted by the wall versus time. a. Find the impulse exerted by the wall on the cart. b. What is the average force exerted by the wall on the cart? c. If the cart has a mass of 0.448 kg, what is its change in velocity? d. Make a sketch of the situation. Include a coordinate system and explain the significance of the signs in parts (a) through (c). FIGURE P11.10arrow_forward
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