Homework #3. PHY 2003 1) A mass hangs from a light string of length 45 cm attach

Question

Homework #3. PHY 2003 1) A mass hangs from a light string of length 45 cm attached at its other end to the ceiling. If the mass is given an initial speed of 5 m/s, what is its speed when it reaches point A in its circular path (see Figure 1)? 2) A 2 kg block slides with initial speed 3 m/s at a height 1 m above ground down an irregularly shaped slope (see Figure 2). If the force of friction does-13 J of work determine the speed of the block at the bottom of the slope. 3) During a vertical fall, a block's speed increases from 6 m/s to 8 m's over a 3 m distance (see Figure 3). What percentage of the block's energy is dissipated due to air resistance over this distance? 4) A 1000 kg car accelerates from 10 m/s to 20 m/s in 2 seconds. Determine the net average power delivered to the car 5) A 10 g bullet is fired at 200 m/s into a 1 kg block, after which they slide together 2 m on a horizontal surface (see Figure 5). Determine the coefficient of kinetic friction between the block and the surface. u2 1 urt 3m que 5 am

Explanation / Answer

3.

Initial energy of the block

Uinitial=mgh+(1/2)mVi2=m(9.8*3+(1/2)*62)=47.4m

final energy of the block

Uf=(1/2)*m*82=32 m

percentage of blocks energy dissipated due to air resistance

=[(47.4-32)/47.7]*100=32.3 %

Related Questions

Navigate

• Browse (All)
• Browse H
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.