Answer:
i) kinetic friction; ii) The friction force always acts in the opposite direction to the movement of the surface where friction exists.
Explanation:
Part i )
At that time the type of friction that exists is kinetic, as there is movement by the wheel. At the moment when the wheel remains in rest over the inclined plane, the friction force which would be used will be the static force.
Part ii)
The friction force always acts in the opposite direction to the movement of the surface where friction exists. It is not opposed to the sense of movement. In order for the wheel to rise on the inclined plane, it must turn to the right, that is to say in the clockwise direction, therefore the friction force must go in the opposite direction to the rotation of the wheel, that is to say, go in the opposite direction to the movement of the surface under friction effect, that is why it points in the same direction of displacement of the wheel.
The only condition under which a concave mirror forms a virtual and upright image on the principal axis is when there is a concave mirror with the object in front of the focal point. This is the only positioning available for the said image to be formed.
The fine horizontal scratches etched onto a bullet after it has been fired are called Striations.
<h3>What is Striations?</h3>
- Striations are the minute differences in the curve of the bullet's surface. The bullet and the gun barrel are the harder and softer materials, respectively, in firearms evidence.
- The striations left on the fired bullet are used as a comparison by firearm examiners.
- When a gun is discharged, the bullet blasts down the barrel where it strikes ridges and grooves, spinning and improving shot accuracy.
- These ridges cause striations in the bullet's soft metal by digging into it.
- An examiner analyses these distinctive markings to verify whether a given bullet was shot from a specific firearm.
- A barrel will produce individual markings in addition to a bullet's land and groove impressions as the projectile passes through.
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Answer:
The expression for the magnitude of the accelerations is
Explanation:
According the Newton´s second law:
Clearing T for second equation:
T = ma + mg
Replacing in the first equation:
Mg - ma - mg = Ma
Ma + ma = Mg - mg
a(M + m) = g(M - m)
1.
Answer:
Hand on book
Earth on book
Explanation:
Since we are holding the book so the forces that acts on the book is
1. Hand on book
this is the contact force between hand and the book
2. Earth on book
here this is the gravitational attraction force of earth on the book
2.
Answer:
A. book on hand - NA
B. hand on book - upwards
C. floor on book - NA
D. earth on book - downwards
Explanation:
Since book is holding in hand so at equilibrium position we can say that the forces on the book must be in equilibrium
so first of all the force of attraction due to earth on the book is downwards and this is counterbalanced by the force of hand on book which is upwards.
3.
Answer:
A. book on hand
Explanation:
As per Newton's III law we know that every action has equal and opposite reaction.
so if our hand apply the force on the book in upward direction then book will apply same magnitude force on the hand in downward direction.