Fairly Simple Problem help kinda

  • Thread starter Thread starter tuckingfypoz
  • Start date Start date
AI Thread Summary
A ball dropped from a building passes a 3-meter window in a quarter of a second. To find the height of the roof above the window, the distance to the window is set as an unknown variable h. The time taken for the ball to fall to h and to h-3 is calculated, with the difference in time equating to 1/4 second. By applying the equations of motion, the problem can be solved for h. This analysis leads to determining the height of the roof from the top of the window.
tuckingfypoz
Messages
1
Reaction score
0
Fairly Simple Problem help... kinda urgent

a ball is dropped off the roof of a building and passes a 3 meter window in a quarter of a second. How high is the roof from the top of the window?
 
Physics news on Phys.org
Set the distance to the window to some unknown h and calculate the time it would take to fall to h, the time it would take to fall to h-3, and solve for h given this difference is 1/4 second.
 
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top