Acar covers 72 kilometers in the first hour of its journey. in the next hour, it covers 90 kilometers. what is the amount of work done by the car? the total mass of the car, including its passengers, is 2.5 × 103 kilograms.
a. 2.8 × 105 joules
b. 4.0 × 105 joules
c. 5.1 × 105 joules
d. 2.8 × 106 joules
e. 2.8 × 107 joules

The amount of work done can be solved using the formula:

Work = Force x Distance = Change in kinetic energy

Kinetic energy can be solved using the formula: KE = (1/2)*m*v^2
So, change in kinetic energy = (1/2)*m*(Vf)^2 - (1/2)*m*(Vo)^2

Where:

Vf = final velocity = 90 kph = 25 m/s
Vo = initial velocity = 72 kph = 20 m/s

substituting the given values:

Work = (1/2)*2500*(25^2) - (1/2)*2500*(20^2) = 281250 J, which can also be expressed as 2.8 x 10^5 Joules.

Among the choices, the correct answer is A.

Scissors and a seesaw both cut things that’s the only comparison

The boat's velocity relative to the riverbank can be resolved into two components. the component going north is 2.7 m/s and the component going west is 1.2 m/s.we add these two vectors and then find the magnitude of the resultant to get the speed.the magnitude of the resultant vector from adding can be obtained by the pythagorean theorem.    to two significant figures, the boat's speed relative to the riverbank is 3.0 m/s.