Okay! Last question was a warm-up question. And now to get your brain thinking some more, how about another one?:
1 answer:
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Answer:
Explanation:
Magnetic field near current carrying wire
=
i is current , r is distance from wire
B = 10⁻⁷ x
force on second wire per unit length
B I L , I is current in second wire , L is length of wire
= 10⁻⁷ x x 33 x 1
= 3234 x
This should balance weight of second wire per unit length
3234 x = .075
r = x 10⁻⁷
= .0043 m
= .43 cm .
Before going to solve this question first we have to understand specific heat capacity of a substance .
The specific heat of a substance is defined as amount of heat required to raise the temperature of 1 gram of substance through one degree Celsius. Let us consider a substance whose mass is m.Let Q amount of heat is given to it as a result of which its temperature is raised from T to T'.
Hence specific heat of a substance is calculated as-
Here c is the specific heat capacity.
The substance whose specific heat capacity is more will take more time to be heated up to a certain temperature as compared to a substance having low specific heat which is to be heated up to the same temperature.
As per the question John is experimenting on sand and water.Between sand and water,water has the specific heat 1 cal/gram per degree centigrade which is larger as compared to sand.Hence sand will be heated faster as compared to water.The substance which is heated faster will also cools faster.
From this experiment John concludes that water has more specific heat as compared to sand.
Newton's second law states that the resultant of the forces applied to an object is equal to the product between the object's mass and its acceleration:
where in our problem, m is the mass the (child+cart) and a is the acceleration of the system.
We are only concerned about what it happens on the horizontal axis, so there are two forces acting on the cart+child system: the force F of the man pushing it, and the frictional force
acting in the opposite direction. So Newton's second law can be rewritten as
or
since the frictional force is 15 N and we want to achieve an acceleration of
, we can substitute these values to find what is the force the man needs:
where in our problem, m is the mass the (child+cart) and a is the acceleration of the system.
We are only concerned about what it happens on the horizontal axis, so there are two forces acting on the cart+child system: the force F of the man pushing it, and the frictional force
or
since the frictional force is 15 N and we want to achieve an acceleration of