Question

A particle is thrown at time t=0 with a velocity of 10m/s at an angle of 60 degree with the horizontal from a point on an inclined plane, making an angle of 30 degree with the horizontal. The time when the velocity of the projectile becomes parallel to the incline is ??

A. 2/root 3 sec B. 1/root 3 sec c. root 3 sec d. 1/ 2 root3 sec

EXPLAIN.

Answer 1

Answer:B-1/✓3

Explanation:

See,

First we find the total time

T= 2usin(A-B)/gcosB

​where A is the angle the projectile makes with the horizontal and B is the angle that the inclined plane makes with the horizontal.

Therefore using A as 60 and B as 30

T= 2/root 3

Now it says PARALLEL to the inclined plane,

if we make a basic diagram if a projectile motion along inclined plane , we see that at the MIDDLE, the velocity is TAGENTIAL to the curve and therefore parallel to the incline.

Hence req time=t/2

which is 1/root 3 sec.