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3 years ago

Mains electricity is an ac supply. Explain the difference between direct and alternating potential difference.

1 answer:

5 0

Direct current (DC) is the flow of electric charge in only one direction. It is the steady state of a constant-voltage circuit. Most well-known applications, however, use a time-varying voltage source. Alternating current (AC) is the flow of electric charge that periodically reverses direction.

<h2>#LETS STUDY</h2>

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David is driving a steady 28.0 m/s when he passes Tina, who is sitting in her car at rest. Tina begins to accelerate at a steady

rodikova [14]

Answer:

Explanation:

Let t represent the time for Tina to catch David.

Hence, considering the equation of linear motion S = ut + 1/2at^2..... 1

For David u = 28.0 m/s where 'a' is set to nought

S = ut

S = 28t.......2

For Tina consider equation 1

Where acceleration = 2.90m/s^2 and u is set at nought

S = 1/2×2.90 m/s×t^2.......3

Equate 2 and 3

28t = 1.45t^2

Divide through by t

28 = 1.45t

t = 28/1.45

t = 19.31seconds

Now put the value of t into equation 3

S = 1/2×2.90 m/s×t^2.......3

= 1.45×20×20

= 580m

Tina must have driven 580meters before passing David

Considering the equation of linear motion : V^2 = U^2+2as

Where u is set at nought

V^2 = 2as

V^2 = 2×2.9×580

V^2 = 3364

V = √3364

V = 58m/s

Her speed will be 58m/s

7 0

3 years ago

Two blocks with mass M and 3M on a horizontal frictionless surface are pushed together and compress a spring of negligible mass

Naily [24]

Answer:

launching speed of the lighter block = -6 m/s

Explanation:

We are given;

Mass of light block; M

Mass of heavy block; 3M

Speed of launched block: v = 2m/s

We are told that the two blocks are sitting on the horizontal frictionless surface. Thus, we can say that no external force is being applied on the system and so, the momentum of the whole system is conserved accordingly to that condition.

We are also told that when the rope is cut with scissors, that the heavier block attains the speed of 2 m/s in the positive x-direction which is horizontal direction.

We know that formula for momentum is; M = mass x velocity.

Thus, the momentum of the heavier block is calculated as;

M_1 = 3M × 2

M_1 = 6M kg.m/s

Since no external force is applied on the object, the initial momentum will be zero.

Hence, to conserve the system, the momentum of the lighter block will be equal and opposite to the momentum of heavier block.

So, momentum of lighter block is;

M_2 = -6M kg.m/s

Since mass of lighter block is M and formula for momentum = mass x velocity.

Thus;

-6M = Mv

Where v is speed of lighter block.

So, v = -6M/M

v = -6 m/s

7 0

3 years ago

The figure shows a 1 cm cube that has a mass of 1 gram. Calculate the density of the cube in kg/m³.

dolphi86 [110]

Density = 1 g/cm^3 = 1000 Kg/m^3

3 0

3 years ago

suppose you needed to build a raft to cross a fast-moving river. Describe the physical and chemical properties of the raft that

erastovalidia [21]

1.Density of the material building the raft must be lower than the water.
2. Material must not react with water. 
3.Material must have high strength. 
4.Raft must be wide in-order to avoid drawing in the river.

4 0

3 years ago

All Physicsts over here plz help in these questions!!!!!!!!!

mrs_skeptik [129]

Hello!

First one we can use that PE=mgh so we have

4.37*10^5J/(9.12*10^3kg*9.80m/s^2)= 4.89m

Second one we can use Newton’s Second Law
F=ma and in this case F=mg so we have

g= 3.28*10^-2N/6*10^-3kg = 5.47m/s^2

Hope this helps. Any questions please ask. Thank you.

6 0

3 years ago

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