Kinetic energy depends on the mass and the speed of a moving object.
If the speeds are equal, then the rick with more mass has more kinetic energy.
Answer:
The efficiency of the system is 63.7 %
Explanation:
Given;
input power of the motor, = 1.5 kW = 1,500 W
mass of the car lifted, m = 1300 kg
height through which the car was lifted, h = 1.8 m
time, t = 24 s
The output power of the motor is calculated as;
Output Power = F x v
= (mg) x (d/t)
= (1300 x 9.8) x (1.8 / 24)
= 12,740 x 0.075
= 955.5 W
The efficiency of the system is calculated as;

The correct answer is 63.7%
Kinetic energy = mass time squared speed divided by 2
W=mv^2/2 = 50*10*10/2 = 2500 J
In order to change the direction and speed, a net external force is required. A net external force is an unbalanced force which will change the direction and gives the speed in the opposite direction. Hence, its an unbalanced force from the joey that pushes the car in the other direction due to which it the car starts to move back to Leah. Without, unbalanced force there is not change in the direction of the car's motion.
Hence, option B is correct.
Answer:
The maximum torque in the coil is
.
Explanation:
Given that,
Number of turns in the circular coil, N = 50
Radius of coil, r = 5 cm
Magnetic field, B = 0.5 T
Current in coil, I = 25 mA
We need to find the magnitude of the maximum possible torque exerted on the coil. The magnetic torque is given by :

For maximum torque, 

So, the maximum torque in the coil is
.