PHYSICS

```PHYSICS
[1pt]
A 50-kg shell is fired from a gun with a muzzle velocity 75 m/s at 74o above the horizontal. At the top of the trajectory, the shell explodes into two fragments of equal mass. One fragment, whose speed immediately after the explosion is zero, falls vertically. What is the horizontal speed of the other fragment?```

2.[1pt]
Two identical steel balls, each of mass 2.9 kg, are suspended from strings of length 29 cm so that they touch when in their equilibrium position. We pull one of the balls back until its string makes an angle theta = 31owith the vertical and let it go. It collides elastically with the other ball. How high will the other ball rise above its starting point?

3.[1pt]
Suppose that instead of steel balls we use putty balls. They will collide inelastically and remain stuck together after the collision. How high will the balls rise after the collision?

4. [1pt]
A bullet of mass m= 3.40×10-2kg is fired along an incline and imbeds itself quickly into a block of wood of mass M= 1.45kg. The block and bullet then slide up the incline, assumed frictionless, and rise a height H= 1.25m before stopping. Calculate the speed of the bullet just before it hits the wood.

5.[1pt]
A car, mass m1 is moving to the right on a frictionless air track. It collides with a second car, mass m2, which is initially at rest. Which of the following statements are true? (If A and E are true, and the others are not, enter TFFFT).

A) If car 1 is much lighter than m2, and the collision is perfectly elastic, car 1 will continue heading to the right with nearly its original speed after the collision.
B) If car 1 sticks to car 2, the car1-car2 system must move to the right after the collision.
C) If car 1 sticks to car 2, the final total kinetic energy of the car1-car2 system is less than the initial total kinetic energy of the two cars.
D) If the collision is elastic, car 1 must always come to a stop after the collision.
E) Suppose (for this statement only) that car 2 was NOT initially at rest, but was instead heading towards car 1 with equal (but opposite) momentum before the collision. After the collision, the cars must both be at rest.

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