D. velocity includes rate of change and direction
Answer:
= 54,000 Joules or 54 kJ
Explanation:
Electrical energy is given by the formula;
E = VIt; where V is the potential difference in volts, I is the current and t is the time in seconds.
Therefore;
Electrical energy = 120 V × 0.50 A × 15 ×60 seconds
= 54,000 Joules
Thus; the electrical energy is 54,000 joules or 54 kJ
Answer:
VR = 
Explanation:
A machine is a device that can be used to overcome a load by the application of an effort through a pivot. Examples are: pulleys, wedge, screw jack, wheel and axle etc.
The wheel and axle is a simple device that can be used to lift a load through a height. Its velocity ratio (VR) can be determined by:
VR = 
Note that for a practical wheel and axle, the radius of the wheel is greater than the radius of the axle.
Answer:
the rate of change in volume with time is 280πr² cm³/min
Explanation:
Data provided in the question:
Radius of the sphere as 'r'
= 70 cm/min
Volume of the sphere, V =
Surface area of the sphere as 4πr²
Now,
Rate of change in volume with time,
=
=
Substituting the value of 
=
= 280πr² cm³/min
Hence, the rate of change in volume with time is 280πr² cm³/min
Answer: The correct answer is option (D).
Explanation:
Voltmeter is a device which measures the the voltage applied across the circuit. It is an electrical instrument used to measure the electric potential between the two points in an electric circuit.
Where as:
A switch is the device which used to connect or disconnect the circuit.
Resistor is a device which opposes the flow of current is an electric circuit.
An ammeter the is an electrical device which measures the amount of current in flowing in amperes in an electrical circuit
Hence,the correct answer is option (D).