Answer:
4334.4 J
Explanation:
Work done equals to kinetic energy change
KE=½mv²
Change in KE is given by
∆KE=½m(v²-u²)
Where m is mass of water-skier, KE is kinetic energy, ∆KE is the change in kinetic energy, v is final velocity and u is initial velocity.
Substituting 72 kg for m, 12.1 m/s for v and 5.10 m/s for u then
∆KE=½*72(12.1²-5.10²)=4334.4J
Therefore, the work done by the net external force acting on the skier is equal to 4334.4 J
To solve this problem we will apply Newton's second law and the principle of balancing Forces on the rope. Newton's second law allows us to define the weight of the mass, through the function
Here,
m = mass
a = g = Gravitational acceleration
Replacing we have that the weight is
Since the rope is taut and does not break, the net force on the rope will be zero.
Therefore the tensile force in the rope is 98N
Answer: 25.2 km
<u>Explanation:</u>
3 blocks east and four blocks east = 7 blocks
1 block = 0.3 km --> 7 blocks = 2.1 km
12 times 2.1 km = 25.2 km
