A donkey is attached by a rope to a wooden cart at an angle of 23 $\circ$ to the horizontal.The tension in the rope is 210 N.If the cart is dragged horizontally along the floor with a constant speed of 6 km/h,calculate how much work the donkey does in 35 minutes.
A)740 kJ
B)290 kJ
C)680 kJ
D)11 kJ
E)0.70 kJ

Question

Quizplus · Accepted Answer

The work done by the donkey is given by the expression: Work = Force x Distance x Cosine of angle

We need to first find out the distance travelled by the cart in 35 minutes (since we are given the speed in km/h, we convert it to m/s):

Speed = 6 km/h = 1.67 m/s
Time = 35 minutes = 2100 seconds
Distance = Speed x Time = 1.67 x 2100 = 3507 meters

Next, we need to find out the angle between the force and the displacement. Since the cart is being dragged horizontally, the angle between the force and displacement is 0 degrees. Therefore, the cosine of the angle is 1.

Substituting the values in the expression for work, we get:

Work = 210 x 3507 x Cos(0) = 736,770 Joules = 736.77 kJ

Rounding off to the nearest 10 kJ, we get the answer as 680 kJ, which is option C.

A Donkey Is Attached by a Rope to a Wooden ∘\circ∘

A Donkey Is Attached by a Rope to a Wooden $\circ$