Numericals projectile motions

追加: 2026-05-14

[00:00:04]Example of the video here.

[00:00:08]A ball is thrown horizontally from a cliff of height 80 m with a velocity 30 m per second.

[00:00:14]So, we have to find time to reach the ground, horizontal distance covered, and final velocity and magnitude. Okay.

[00:00:24]So, this is your cliff.

[00:00:26]And that is 80 m of height.

[00:00:32]And initially, there is a velocity towards X component X axis.

[00:00:37]X is 30 m per second.

[00:00:43]So, see.

[00:00:45]Considering velocity and distance along Y axis. Okay.

[00:01:03]I mean, vertically.

[00:01:11]We have Py is zero.

[00:01:17]H is 80.

[00:01:20]And acceleration due to gravity is 10 m per second squared.

[00:01:25]These are all meters.

[00:01:27]So, time will be twice root H by G.

[00:01:35]20 80 by 10 That will be root 16. That means 4 seconds.

[00:01:45]So, [snorts] you can understand the time taken will be 4 seconds.

[00:01:51]Okay.

[00:01:54]Now, horizontal distance covered.

[00:01:57]SX will be VX into T.

[00:02:01]VX is 30 and T is 4. So, that will be 120 m.

[00:02:09]Okay. So, these are the answers and at last we have to find the final velocity.

[00:02:22]Okay.

[00:02:23]So, the velocity along X axis will remain constant. Velocity VX will remain 30.

[00:02:31]What will be the VY? VY will be G into T. So, 10 into 4, that will be 40.

[00:02:40]Now, you have two velocity that is acting perpendicularly to each other. That is VX and VY.

[00:02:48]The resultant will be velocity like this and the resultant velocity will be VR equal to VX plus VY squared.

[00:02:58]That is 30 squared plus 40 squared under root. So, that will be 50 squared under root, that means 50.

[00:03:10]So, final velocity will with the object 50 m/s.

[00:03:30]So, these are the answers.

[00:03:32]We have time is 4 seconds.

[00:03:35]Distance covered along X axis is 120 m and final velocity will be 50 m/s.