1.

A ball rolls off the top of a stairway with a horizontal velocity of magnitude 150 cm/sec. The steps are 20 cm high and 20 cm wide. Which step will the ball hit first?

Answer» <html><body><p></p>Solution :Let x be the horizontal distance measured from the foot of the edge of the step, the <a href="https://interviewquestions.tuteehub.com/tag/ball-891849" style="font-weight:bold;" target="_blank" title="Click to know more about BALL">BALL</a> leaves the <a href="https://interviewquestions.tuteehub.com/tag/top-1422115" style="font-weight:bold;" target="_blank" title="Click to know more about TOP">TOP</a> of stairway to the point it hits the nth step. <br/> `x=v_(0)t=1.5t`. …………….i <br/> where `v_(0)` is the initial horizontal <a href="https://interviewquestions.tuteehub.com/tag/speed-1221896" style="font-weight:bold;" target="_blank" title="Click to know more about SPEED">SPEED</a>. The height of the ball drops through is <br/> `y=nH=0.2n`..........ii <br/> Where n is the <a href="https://interviewquestions.tuteehub.com/tag/numer-1126556" style="font-weight:bold;" target="_blank" title="Click to know more about NUMER">NUMER</a> of steps and H=20cm is the height of each step. As the vertical component of initial velocity is zero, the vertical distance <a href="https://interviewquestions.tuteehub.com/tag/traversed-7717243" style="font-weight:bold;" target="_blank" title="Click to know more about TRAVERSED">TRAVERSED</a> in the same time t is <br/> <img src="https://doubtnut-static.s.llnwi.net/static/physics_images/AKS_ELT_AI_PHY_XI_V01_A_C05_SLV_023_S01.png" width="80%"/> <br/> `y=1/2"gt"^(2)`........iii <br/> and `x=nw=0.2`n.......iv <br/> `x=y=0.2n`........iv <br/> `V_(0)t=1/2"gt"^(2),t=(2V_(0))/g=(2xx150xx10^(-2))/10` <br/> `impliest=0.3s` <br/> `:.0.2n=1.5(0.3)impliesn=2.25m:.n=3`</body></html>


Discussion

No Comment Found

Related InterviewSolutions