Answer:
No, not necessarily
Explanation:
If an object is moving with an acceleration that causes its speed to be reduced, there will be a moment in which it reaches v = 0, but this doesn't necessarily mean that the acceleration isn't acting anymore. If the object continues its movement with the same acceleration, it's velocity will become negative.
An example of an object that has zero velocity but non-zero acceleration:
If you throw an object in the air with a certain velocity, it will move vertically, reducing its velocity in a 9,8 
rate (which is the acceleration caused by gravity). At a certain point, the object will reach its maximum height, and will start to fall. In the exact moment that it reaches the maximum height, before it starts falling, its velocity is zero, but gravity is still acting on the object (this is the reason why it starts falling instead of just being stopped at that point). Therefore, at that point, the object has zero velocity but an acceleration of 9,8 .
A higher temperature, stiffer materials, and less dense materials increase the speed of sound.
Answer:
Not be changed
Option: D
<u>Explanation:</u>
The physical quantity which has both ‘magnitude and direction’ is called vector. These vectors are represented by a line and an arrow, <em>the line represent the magnitude and arrow represent the direction of the physical quantity</em>. The vectors are added and subtracted according to the direction of the vectors.
According to the vector law addition while adding vectors direction and length of the vector is not be changed.<em> If the length of the vector changed the magnitude is also changed while so, while adding vectors length must not be changed.
</em>
Answer: current I = 0.96 Ampere
Explanation:
Given that the
Resistance R = 60 Ω
Power = 55 W
Power is the product of current and voltage. That is
P = IV ...... (1)
But voltage V = IR. From ohms law.
Substitutes V in equation (1) power is now
P = I^2R
Substitute the above parameters into the formula to get current I
55 = 60 × I^2
Make I^2 the subject of formula
I^2 = 55/60
I^2 = 0.92
I = sqr(0.92)
I = 0.957 A
Therefore, 0.96 A current must be applied.
