Answer to Question #306988 in Mechanics | Relativity for Krissy

Question

26. A ball with a horizontal speed of 1 m/s rolls off a bench 2 m high.

How long will the ball take to reach the floor?

How far from a point on the floor directly below the edge of the bench will the ball land?

27. An electron is ejected horizontally at a speed of 1.5 X10⁶ m/s from the electron gun of a computer monitor. If the viewing screen is 35 cm from the end of the gun, how far will the electrons travel in the vertical direction before hitting the screen?

Answer 1

Solution.

$26. h=2m;$

$v=1 m/s;$

$t-?;$

$L-?;$

$h=\dfrac{gt^2}{2}\implies t=\sqrt{\dfrac{2h}{g}};$

$t=\sqrt{\dfrac{2\sdot2}{9.8}}=0.64s;$

$L=vt;$

$L=1\sdot0.64=0.64m;$

$27. v=1.5\sdot 10^6 m/s;$

$L=0.35m;$

$L=vt\implies t=\dfrac{L}{v};$

$t=\dfrac{0.35}{1.5\sdot10^6}=0.23\sdot10^{-6}s;$

$h=\dfrac{gt^2}{2};$

$h=\dfrac{9.8\sdot (0.23\sdot10^{-6})^2}{2}=0.26\sdot10^{-12}m;$

Answer:$26. t=0.64s; L=0.64m;$

$27. t=0.23\sdot10^{-6}s; h=0.26\sdot10^{-12}m.$