Answer:
the minimum value of torque is 101.7 N-m.
Explanation:
Given that,
Mass of bundle of shingles, m = 30 kg
Upward acceleration of the shingles,
The radius of the motor of the pulley, r = 0.3 m
Let T is the tension acting on the shingles when it is lifted up. It can be calculated as :
T-mg=ma
T=m(g+a)

Let
is the minimum torque that the motor must be able to provide. It is given by :

the minimum value of torque is 
Briefly outline the caloric theory about the nature of heat
Answer:
Explanation:
From the question we are told that
The initial velocity is 
The time taken is 
The charge to mass ratio is 
Generally the acceleration is mathematically evaluated as

substituting values

The electric field is mathematical represented as

substituting values


Answer:
A moving electric charge creates a magnetic field at all points in the surrounding region.
An electric current in a conductor creates a magnetic field at all points in the surrounding region.
A permanent magnet creates a magnetic field at all points in the surrounding region.
Explanation:
Magnetic field can be produced by:
- moving charges (i.e. a moving electron, or a current in a conductor)
- A magnet
The strength of the magnetic field produced by a current-carrying wire is

where
I is the current
r is the distance from the wire
As we see from the formula, the magnetic field is produced at all points in the surrounding region, because B becomes zero only when r becomes infinite. The same is true for the magnetic field created by a single moving charge or by a magnet.
The following choices instead are not correct:
- A single stationary electric charge creates a magnetic field at all points in the surrounding region.
- A distribution of electric charges at rest creates a magnetic field at all points in the surrounding region.
Because they involve the presence of stationary charges, and stationary charges do not produce magnetic fields.
Answer:
D. Because mass and energy are both conserved, the total amounts of mass and energy are the same before and after impact.
Explanation:
As we know that, the energy in motion is Kinetic Energy mathematically given as:

<u>Now, according to the law of conservation of energy:</u>

where:
mass of racquet and ball respectively and
are their respective initial velocities.
are the respective final velocities.
<u>Also the law of conservation of momentum is applicable in this case:</u>

In this case the velocity of the lighter mass will get increases in the final condition.