(1)A battery drives 60c of charge in a circuit for 20s. Thecurrent in the circuit is?(2)What is the volume of a block of expanded polystyrene of 400g and density 16kg/m3?(3)The velocity of a toy car of mass 2kg increased from 5m/s to 10m/s in 2seconds.What force was exerted on the car?(4)A stone of mass 2kg is dropped from a height of 3metres neglection air resistance the kinetic energy in joules of the stone just befor it hits the ground is?(5)An object initially travelling at a velocity of 10m/s changes its velocity to 30m/s in 40seconds calculate the acceleration?
(1) To determine the current in the circuit, you can use Ohm's Law, which states that current (I) is equal to the ratio of the charge (Q) passing through a conductor to the time (t) taken for the charge to pass through.
The formula for calculating current (I) is: I = Q / t
Given that the battery drives 60c (60 coulombs) of charge in a circuit for 20 seconds, you can substitute these values into the formula:
I = 60c / 20s = 3A
Therefore, the current in the circuit is 3 amperes.
(2) To find the volume of the expanded polystyrene block, you can use the formula:
Volume = Mass / Density.
Given that the mass of the block is 400g (0.4kg) and the density is 16kg/m^3, you can substitute these values into the formula:
Volume = 0.4kg / 16kg/m^3 = 0.025m^3.
Therefore, the volume of the expanded polystyrene block is 0.025 cubic meters.
(3) To calculate the force exerted on the toy car, you can use Newton's second law of motion, which states that force (F) is equal to the product of mass (m) and acceleration (a):
The formula for calculating force (F) is: F = m * a.
Given that the mass of the toy car is 2kg and the change in velocity is from 5m/s to 10m/s in 2 seconds, you can substitute these values into the formula:
Acceleration (a) = (Change in Velocity) / (Time) = (10m/s - 5m/s) / 2s = 5m/s^2.
Now, substitute the mass and acceleration values into the force formula:
F = 2kg * 5m/s^2 = 10N.
Therefore, the force exerted on the car is 10 Newtons.
(4) To calculate the kinetic energy of the stone just before it hits the ground, you can use the formula for kinetic energy, which is given by:
Kinetic Energy (KE) = 1/2 * mass * velocity^2.
Given that the mass of the stone is 2kg and it is dropped from a height of 3 meters (which does not affect its kinetic energy since no work is done against gravity), you can use the equation:
Potential Energy (PE) = mass * gravity * height.
Potential Energy (PE) = 2kg * 9.8m/s^2 * 3m = 58.8 J.
Since potential energy is converted into kinetic energy during the fall:
Kinetic Energy (KE) = Potential Energy (PE) = 58.8 J.
Therefore, the kinetic energy of the stone just before it hits the ground is 58.8 Joules.
(5) To calculate the acceleration, you can use the formula:
Acceleration (a) = (Change in Velocity) / (Time).
Given that the object initially travels at a velocity of 10m/s and changes its velocity to 30m/s in 40 seconds, you can substitute these values into the formula:
Acceleration (a) = (30m/s - 10m/s) / 40s = 0.5m/s^2.
Therefore, the acceleration of the object is 0.5 meters per second squared.