PROBLEMS. SHOW ALL WORK. ROUND ANSWERS TO THE PROPER NUMBER OF SIGNIFICANT FIGUR

Question

PROBLEMS. SHOW ALL WORK. ROUND ANSWERS TO THE PROPER NUMBER OF SIGNIFICANT FIGURES. 11. Allie exerts a force of 186 N on a lever to raise a 2.70 x 10 N object to a height of 29.0 cm. If the efficiency of the lever is 83.3%, how far does Allie move her end of the lever? 12. You pull your dog on a sled through the snow. You pull on the rope at an angle of 27 from the horizontal and exert a force of 75 N on the rope. The sled move horizontally a distance of 950 m. How much work did you do on the rope? a velocity of 19.5 m/s. Calculate the power required to reduce the 13. A 1600 kg car moves with velocity to 3.20 m/s in 11.0 seconds.

Explanation / Answer

Given

11.

force applied is Fe = 186 N ,

the load is W = 2.70*10^3 N to a height 0.29 m

thelever efficiency is 83.3 % = 0.833

we know that the efficiency is Fe*S /(W*h)  

0.833 = 186*s /(2700*0.29)

s = 3.5066 m

so allie should move her end of the lever is 3.51 m

12. Work done W= F*S cos theta

W = 75*950 cos27 J

W = 63484.215 J

the work done on the rope by applying force f is W = 63484.215 J

13.

m = 1600 kg ,

v = 19.5 m/s

power required to reduce the velocity to 3.20 s in time 11 s is P =?

P = W/T = d K.e /dt

P = 0.5*m(v2^2-v1^2)/dt

P = 0.5*1600(3.20^2-19.5^2)/11 W

P = -26909.82 W  

-ve sign indicates the car is decelerating (-ve work done)

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---

---

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