16If you guys want,I can upload a rough sketch for the sum.
A motorcyclist starts from the bottom of a slope of angle 45° to cross a valley. The width of the valley 90m and length of the slope is 80√2m. What is the minimum value of u (initial velocity)?
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3 Answers
16
263Let the velocity of the man at the topmost point of the slope be v.Now from here projectile motion starts at an angle of 45.
So v2=900.....[as θ=45]
or, v=30.
Now along the incline decelaration=gsin45.
So u2 - v2=2*gsin(45)*80√2.
or, u=50. This is the minimum required speed.
- ARKADYUTI BANDYOPADHYAY Is it necessary to take the component of deceleration along the incline? Can't we just calculate the horizontal distance covered (using either sine or cosine to solve for the value of the perpendicular distance and the horizontal distance covered)Upvote·0· Reply ·Jun 20 at 4:57
- ARKADYUTI BANDYOPADHYAY Sorry for the typo in my previous comment - it should be perpendicular distance covered.
16Sorry, I did not get your solution. I worked it out on my own. The answer is correct though. It IS 50 m/s.
- ARKADYUTI BANDYOPADHYAY Should I show how I CALCULATED the answer? Akash sir? What do you say?
Akash Anand Yeah post it.