Answer:
Images formed by a convex mirror are always virtual
Explanation:
A virtual image is always created by a convex mirror, and it is always situated behind the mirror. The picture is vertical and situated at the focus point when the item is far away from the mirror. As the thing approaches the mirror, the image follows suit and increases until it reaches the same height as the object.
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Cetane rating of the diesel ensures the low temperature and uniform combustion. Centane number is just opposite to the octane number of petrol engine, cetane number of diesel determines at which temperature the diesel will going to autoignite.
Answer:
d) The speed of the astronaut
Explanation:
The sentence describes the speed of the astronaut. This speed value is 10meters per minute.
Now let us understand why;
- Speed is the distance divided by time. It is a scalar quantity without regard for direction but it has magnitude.
- The value 10meters per minute clearly shows this instance. We do not know the direction the astronaut is moving towards.
- Velocity, like speed is the displacement of a body with time. It is a vector quantity and it shows the direction of motion.
- For example, 10m/s due west is a velocity value because we know the direction.
Therefore, since there is no directional sense, the value indicates speed.
Answer:
Here the source is moving away from the observer so frequency will be smaller than the actual frequency and since the speed is increasing so the frequency is decreasing with time so correct answer is
D) lower than the original pitch and decreasing as he falls.
Explanation:
As we know by the Doppler's effect of sound we have
so we will have

so here when source moves away from the observer with a some speed then the frequency of the sound observed by the observer is smaller than the actual frequency
Here we know that the speed of the source is increasing with time as the source is falling under gravity
So we can say that the pitch of the sound will decrease with time
Answer:
horizontal component of normal force is equal to the centripetal force on the car
Explanation:
As the car is moving with uniform speed in circle then the force required to move in the circle is towards the center of the circle
This force is due to friction force when car is moving in circle with uniform speed
Now it is given that car is moving on the ice surface such that the friction force is zero now
so here we can say that centripetal force is due to component of the normal force which is due to banked road
Now we have


so we have

so this is horizontal component of normal force is equal to the centripetal force on the car