7. When a 0.38-kg block is suspended on a vertical spring, it causes it to stretch 3.30 cm. If the block is now pulled 8.50 cm below its equilibrium position and released, what is the speed of the block when it is 4.00 cm below the equilibrium position? MAI 2 x 0.37 m/s CA SUI v m

2. A 35 kg child is riding on a swing. At her highest point she is 1.8 m above the ground, at her lowest point she is 0.5 meter above the ground. Find her maximum specd in m/s

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A 2.5-kg block is held at rest against a spring (? = 1200 N/m), compressing it ? = 5.0 cm from its equilibrium position, then released. There is no friction except where indicated otherwise. A. Just to the right of point ?, the block traverses a rough section, (represented by the thick line between ? and ?), losing half of its kinetic energy to friction. What is the block’s speed at point ?? B. The rough section described in part (c) is 20 cm long. What isthe coefficient of kinetic friction?

A crane lifts a 268 kg crate a height of 12.4 m in a time of 80.0 s at a constant speed. What is the crane's power? Select one: 41.5 W Ob. 4.08 x 102 W O c. 3.32 x 10³ W O d. 3.26 x 104 W a. The time required for one complete oscillation of a vibrating object is called

5. A 60 kg circus performer is swinging from a trapeze bar.A: She is 10 m off the ground with a speed v1. The spring-board platform below her is atits equilibrium length.B: She lets go of the trapeze bar and lands on th spring-board platform, which compresseswhen she lands on it. When she is stationary, she is 2 m off the ground and the springis maximally compressed.C: The spring-board extends and launches her back into the air. As soon as the spring istotally relaxed again, the performer is 3 m off the ground and has a speed v2.D: The performer lands on a platform 10 m above the floor, and she stands stationary. a. Her initial speed v1 = 10 m/s. What is her total energy at point A?  b. Between points A and B, assume none of her energy is lost to heat or friction. Whenshe is stationary on the compressed platform at B, how much energy is stored in thespring-board platform?  c. When the spring-board platform is fully released at point C, what must her speed v2 be?

2. An object has 560 J of potential energy and 890 J of mechanical energy. How much kinetic energy does the object have?. ME = REHPE 560 560 330J= PE olog ertev 3. A slingshot rubber band with a spring constant of 850 N/m was stretched 0.33 m. A 0.4 kg rock was fired from the slingshot after it was released. a. Find the spring potential energy. PE =)2 kx? Z(850X.33) b. What is the kinetic energy of the stone once it was released? PEERE c. What is the velocity of the stone as soon as the slingshot was released?

4. A 3kg block sits on a ramp, against a spring. I pull back on the block, compressing the string by 4cm, and the block moves 1.4m up the ramp, so that it is 0.5m higher than it was before, before it stops. If the force of kinetic friction on the block from the ramp is K = 7N, find the spring constant k. Ef = Ei 0.5m + 1.4m W

9. If an object is released from the position A on the top of the hill. What will be its speed at the peak C. Assume the track is frictionless. AA h,- 50 m = 30 m B

A 1.2 m spring is standing on one end. A 60-kg block is placed on the spring, compressing it. What is the length of the compressed spring if spring constant k is 500 N/m? y Lo Yeq 0 www Before Compressed After