.png)
Updated: Jul 31
For such questions, always look at the blocks as one single system and find the acceleration of the whole as one. That acceleration is the same for both blocks.
Then apply free body diagram (the one with the unknown T and with the least number of forces acting), find the unknown T.
Refer to this post for more examples of such questions (some involve friction)
From the resultant force-time graph, from time to time 0 to t, there is a decreasing resultant force. Using Fnet = ma, as the Fnet decreases, the acceleration is decreasing. But note that decreasing acceleration does not mean speed is decreasing. It means the speed is still increasing, just that the increment is getting smaller per unit time.
After time t, there is not resultant force, hence no acceleration. Since the object is already moving, it will continue to move at constant speed in a straight line.
On the speed time graph, D fits the scenario.
When there is current flowing through the wire, there is magnetic field generated around the wire. To determine the direction of the magnetic field, we can use Right Hand Grip Rule (RHGR).
To help in the visualisation, we can also use the ‘dot’ and ‘cross’ to represent magnetic field coming out of the paper and into the paper respectively.