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3 years ago

Help me with theses 2 questions please.

Physics

1 answer:

spin [16.1K]3 years ago

4 0

Answer: A inclined plane and staircase reaching the same height. Work depends on initial and final position only.

Explanation:

The amount of work done does not depend on path length. It depends on initial and final position. It is given by gravitational potential energy.

W = m g h

Where, m is the mass of the object, g is the acceleration due to gravity and h is the height.

Let the mass of the object be m. Two different paths ( one inclines plane and another staircase) are taken to same point. The object would gain same gravitational potential energy because it depends on the height through which the object is taken and not the actual path length.

W ∝ h.

Spring constant can be defined as the ratio of amount of force acting spring with the displacement caused due to the force. A deformed elastic object has elastic potential energy stored in it which is equal to the work done to deform the object. It is proportional to the spring constant and amount of stretched distance.

Equilibrium is reached when the net force acting on the spring is zero. In equilibrium state, the object has natural extension. An object is said to possess elastic potential energy when force is applied and object deforms relative to original equilibrium shape or length.

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4 years ago

The haystack maker tractor lifted 120 kg of grass to a height of 5 meters in 6 seconds. Calculate the power of the haystack make

Gelneren [198K]

Answer:

1000 Joules per second.

Explanation:

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3 years ago

Aconstant current of 3 Afor 4 hours is required to charge an automotive battery. If the terminal voltage is V, where t is in hou

kirza4 [7]

Answer:

(a) 43.2 kC

(b) 0.012V kWh

(c) 0.108V cents

Explanation:

<u>Given:</u>

i = current flow = 3 A
t = time interval for which the current flow = $4\ h = 4\times 3600\ s = 14400\ s$
V = terminal voltage of the battery
R = rate of energy = 9 cents/kWh

<u>Assume:</u>

Q = charge transported as a result of charging
E = energy expended
C = cost of charging

Part (a):

We know that the charge flow rate is the electric current flow through a wire.

$\therefore i = \dfrac{Q}{t}\\\Rightarrow Q =it\\\Rightarrow Q = 3\times 14400\\\Rightarrow Q = 43200\ C\\\Rightarrow Q = 43.200\ kC\\$

Hence, 43.2 kC of charge is transported as a result of charging.

Part (b):

We know the electrical energy dissipated due to current flow across a voltage drop for a time interval is given by:

$E = Vit\\\Rightarrow E = V\times 3\times 4\\\Rightarrow E = 12V\ Wh\\\Rightarrow E = 0.012V\ kWh\\$

Hence, 0.012V kWh is expended in charging the battery.

Part (c):

We know that the energy cost is equal to the product of energy expended and the rate of energy.

$\therefore \textrm{Cost}=\textrm{Energy}\times \textrm{Rate}\\\Rightarrow C = ER\\\Rightarrow C = 0.012V\times 9\\\Rightarrow C =0.108V\ cents$

Hence, 0.108V cents is the charging cost of the battery.

4 0

4 years ago