Answer:
C. At a particular instant
Explanation:
Speed is the defined as the ratio between the distance covered by an object and the time taken:
where d is the distance and t the time.
However, there are two possible measurements of speed:
- Average speed: this is the speed measured over a non-zero time interval (for example: a car moving 100 metres in 5 seconds; its average speed is
- Instantaneous speed: this is the speed of an object measured at a particular instant in time, so for a time interval that tends to zero. So, in the previous example, the average speed is 20 m/s but the instantaneous speed of the car at various instants of time can be different from that value.
The gravitational pull of the Sun the interstellar dust attracting heat away from the protosun the process of nuclear fusion the nebular cloud condensing.
<span>The
formation of the Solar System began 4.6 billion years ago with the
gravitational collapse of a small part of a giant molecular cloud. Most
of the collapsing mass collected in the center, forming the Sun, while
the rest flattened into a proto-planetary disk out of which the planets,
moons, asteroids, and other small Solar System bodies formed.
Hope it helped
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Answer:
The first part can be solved via conservation of energy.
For the second part,
the free body diagram of the car should be as follows:
- weight in the downwards direction
- normal force of the track to the car in the downwards direction
The total force should be equal to the centripetal force by Newton's Second Law.
where 
because we are looking for the case where the car loses contact.
Now we know the minimum velocity that the car should have. Using the energy conservation found in the first part, we can calculate the minimum height.
Explanation:
The point that might confuse you in this question is the direction of the normal force at the top of the loop.
We usually use the normal force opposite to the weight. However, normal force is the force that the road exerts on us. Imagine that the car goes through the loop very very fast. Its tires will feel a great amount of normal force, if its velocity is quite high. By the same logic, if its velocity is too low, it might not feel a normal force at all, which means losing contact with the track.
Answer:
Explanation:
Call the bike on the right A
Call the bike on the left B
The car begins it's time when it passes A
4 minutes later, it passes B.
But B has moved in 4 minutes and that is the key to the problem.
How far has B moved.
t = 4 minutes = 4/60 hours = 1/15 of an hour.
d = ?
rate = 30 km / hr
d = r * t
d = 30 km/hr * 1/15 hours = 2 km
The distance between the bikes is 5 km.
So the car has traveled 5 - 2 = 3 km
d = 3 km
r = ?
t = 4 minutes = 1/15 hour
r = d/t = 3/(1/15)= 3 / 0.066666666 = 45 km/hr.
