0.400 kg hammer is moving horizontally at 7.50 m/s when it strikes a nail and comes to rest after driving it 1.00 cm into a board. (a) Calculate the duration of the impact in seconds. (Enter a number.)  s (b) What was the average force in newtons exerted downward on the nail? (Enter a number.)

A 2.00-kg particle has a velocity (2.00i3.00j)m/s, and a 3.00-kg particle has a velocity (1.00i+6.00j)m/s. Find (a) the velocity of the center of mass and (b) the total momentum of the system.

Check Your Understanding Suppose the initial velocities were not at right angles to each other. How would this change both the physical result and the mathematical analysis of the collision?

A ball of mass 250 g is thrown with an initial velocity of 25 m/s at an angle of 30 with the horizontal direction. Ignore air resistance. What is the momentum of the ball after 0.2 s? (Do this problem by finding the components of the momentum first, and then constructing the magnitude and direction of the momentum vector from the components.)

From what might be a possible scene in the comic book The X-Men, the Juggernaut (mJ) is charging into Colossus (mC) and the two collide. The initial speed of the Juggernaut is vJi and the initial speed of Colossus is vCi. After the collision, the final speed of the Juggernaut is vJf and the final speed of Colossus is vCf as they each bounce off of the other, heading in opposite directions. a. What is the impulse experienced by the Juggernaut? b. What is the impulse experienced by Colossus? c. In your own words, explain how these impulses must compare with each other and how they are related to the average force each superhero experiences during the collision.

A 65.0-kg basketball player jumps vertically and leaves the floor with a velocity of 1.80 m/s upward, (a) What impulse does the player experience? (b) What force does the floor exert on the player before the jump? (c) What is the total average force exerted by the floor on the player if the player is in contact with the floor for 0.450 s during the jump?

The magnitude of the net force exerted in the x direction on a 2.50-kg particle varies in time as shown in Figure P9.10 (page 244). Find (a) the impulse of the force over the 5.00-s time interval, (b) the final velocity the particle attains if it is originally at rest, (c) its final velocity if its original velocity is 2.00im/s, and (d) the average force exerted on the particle for the time interval between 0 and 5.00 s. Figure P9.10

In Section 1.4, we considered the collision of a karate expert’s hand with a concrete block. Based on the graphs in Figure 1.31, the initial downward speed of the fist with mass 0.75 kg is about -13 m/s and the collision time is approximately 25 ms. Find the impulse and the average force exerted on the block by the fist during the collision.

Check Your Understanding The changes of momentum for Philae and for Comet 67/P were equal (in magnitude). Were the impulses experienced by Philae and the comet equal? How about the forces? How about the changes of kinetic energies?

When two objects collide, the impulse exerted on object 1 by object 2 is equal in magnitude and opposite and direction to the impulse exerted on object 2 by object 1: I[1on2]=I[2on1](11.8) And the change in their momenta is given by: p1=p2(11.9) Which of Newtons three laws justifies these two equations?