Answer:
v = 6.05 m/s
Explanation:
The mass of the brick, M = 21 kg
The velocity of the brick, U = 6.1 m/s
The mass of the cart, m = 2.9 kg
The velocity of the cart, u = 0.26 m/s
The combined mass of the brick and the cart, v = ?
According to the law of conservation of linear momentum,
Combined final momentum = sum of the initial momentum
(M + m)v = MU + mu
v = MU + mu / M + m
= 21 x 6.1 + 2.1 x 0.26 / (21 + 0.26)
= 6.05 m/s
Hence, the combined velocity of the cart and the brick is, v = 6.05 m/s
Answer : The correct option is, (B)
Explanation :
Electrical energy : It is defined as the movement of the electrons thought the wire.
Chemical energy : It is a type of energy which is stored in the bonds of a chemical compounds. During the chemical reaction, chemical energy is released in the form of heat.
Sound energy : It is a type of energy which is produced when an object vibrate.
Mechanical energy : It is a type of energy that can be used to do work.
The option A is incorrect because in this process, electrical energy being converted to the sound energy.
The option B is correct because in this process, electrical energy being converted to chemical energy. An oxidation-reduction reaction occurs in the storage battery.
The option C is incorrect because in this process, mechanical energy being converted to mechanical energy.
Hence, the option (B) A storage battery is charged using an electric current is an example of electrical energy being converted to chemical energy.
(a) As the car is moving with constant velocity, it means the rate change of velocity does not change, therefore the average acceleration of the car is zero.
Thus, there is no acceleration, when velocity is constant.
(b) Average acceleration,

Here, v is final velocity and u is the initial velocity and
is the time interval.
As twelve seconds later, the car is halfway around the track and traveling in the opposite direction with the same speed, therefore

Thus, the average acceleration of the car is
in the direction to the left.
Answer:
d
He could pull the mass down farther.
Answer: B
D makes no sense because energy is created so we can remove that. C also makes no sense because if energy is not created how did it get destroyed if there's no energy in the first place. This leaves us with a and B the correct answer is B because energy is created and cannot be destroyed.