Answer:
The following options are true based on the properties of electric field;
a) Electric field lines near positive point charges radiate outward.
b) The electric force acting on a point charge is proportional to the magnitude of the point charge.
d) In a uniform electric field, the field lines are straight, parallel, and uniformly spaced.
Explanation:
From option b) From coulomb's law F = Kq1q2r/r2
Answer:
4.545454 seconds
Explanation:
1500/330=4.545454 seconds
Answer:
In a two particle system, the center of mass lies on the center of the line joining the two particles.
Answer:
Average speed of Elain = 60 km/h
Explanation:
Total Distance covered by Jack = 360km
Average Speed of Jack = 80 km/h
Time taken by Jack to complete his journey = Distance / Average speed = 360 km / 80 km/h
Time taken by Jack to complete his journey = 4.5 hours
As it is given the both Jack and Elain travelled the same amount of distance:
Total distance travelled by Elain = 360 km
It is given that Elain took 1.5 hourse more than Jack to cover the distance, so Time taken by Elain to cover the distance is = 4.5 hours + 1.5 hours = 6 hours
Average speed of Elain = Distance/ time = 360 km / 6 hours
Average speed of Elain = 60 km/h
1. In the first 1.5 seconds, the lift accelerates from 0 to 3m/s. By definition, the acceleration is the ratio between the change in velocity and the time elapsed to change the velocity.
The change in velocity is 
.
The time elapsed is 1.5 seconds, so the acceleration is
meters per second squared.
2. We know, from the previous point, that the lift travelled 20m from the first floor. Since it returns to the first floor after the ascent, it must travel again those same 20m, just in reverse (descending instead of ascending). So, the total distance travelled is 
meters.
The displacement, though, is zero, because it measures the distance between the starting and ending point of a certain motion. Since the lift starts and ends its motion at the same place (the first floor), its total displacement is zero.
