A force of 100 N moves a block of mass 10 kg up a plane of length 2 m at an angl

Question

A force of 100 N moves a block of mass 10 kg up a plane of length 2 m at an angle of 30 degree . If the force is parallel to the plane, if the block starts from rest, and if the coefficient of friction is 0.1, how much work is done (a) by the force, (b) by gravity, and (c) by friction. (d) How fast will the block be moving when it gets to the top? An electric motor starts revving up, consuming energy according to the equation W = C t^2, where C = 200 J/s^2 (a) How long does it take for the engine to consume 1000 J of energy? (b) What is the equation giving the power output of the motor? (c) How long does it take for the motor to develop a power output of 1 hp?

Explanation / Answer

6)

a) Work done by force = force * distance

Work done by force = 100 * 2

Work done by force = 200 J

b)

work done by gravity = -mg * d* sin(theta)

work done by gravity = -10 * 9.8 * 2 * sin(30)

work done by gravity = -98 J

c)

work done by friction = -us*mg*cos(theta)

work done by friction = -0.1 * 10 * 9.8 * cos(30)

work done by friction = -8.48 m

d)

Now, let the final speed is v m/s

Using work energy theorum ,

0.5 *10 * v^2 = Net work done

0.5 *10 * v^2 = 200 - 98 - 8.48

v = 4.32 m/s

block will be moving at 4.32 m/s at the top

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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