Answer:
Explanation:
As we know that the resistance of the wire is directly proportional to the length of wire and inversely proportional to the area of crossection of the wire.
As the material is copper for both the wires so the resistivity is same and the voltage is also same. As their resistance is different it means either length is different or the area of crossection is different.
(a) The net force on the shopping cart is zero.
(b) The the force of friction on the shopping cart is 25 N.
(c) When same force is applied to the shopping cart on a wet surface, it will move faster.
<h3>Net force on the shopping cart</h3>
The net force on the shopping cart is calculated as follows;
F(net) = F - Ff
where;
- F is the applied force
- Ff is the frictional force
ma = F - Ff
where;
- a is acceleration of the cart
- m is mass of the cart
at a constant velocity, a = 0
0 = F - Ff
F(net) = 0
F = Ff = 25 N
Net force is zero, and frictional force is equal to applied force.
<h3>On wet surface</h3>
Coefficient of kinetic friction of solid surface is greater than that of wet surface.
Since frictional force limit motion, when the frictional force is smaller, the object tends to move faster.
Thus, the cart will move faster on a wet surface due to decrease in friction.
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If the earth's mass were half its actual value but its radius stayed the same, the escape velocity of the earth would be 
.
<h3>What is an escape velocity?</h3>
The ratio of the object's travel distance over a specific period of time is known as its velocity. As a vector quantity, the velocity requires both the magnitude and the direction. the slowest possible speed at which a body can break out of the gravitational pull of a certain planet or another object.
The formula to calculate the escape velocity of earth is given below:-
Given that earth's mass was half its actual value but its radius stayed the same. The escape velocity will be calculated as below:-
.
Therefore, If the earth's mass were half its actual value but its radius stayed the same, the escape velocity of the earth would be .
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