Help please, I seem to have reached an impasse

Thread starter Cowtipper
Start date Oct 18, 2007

AI Thread Summary

A stone is thrown horizontally from a 50.0 m high cliff at a speed of 18.0 m/s. To determine the speed and angle of impact, the stone's vertical and horizontal motions must be analyzed separately. The time taken to fall 50.0 m can be calculated using the formula for free fall, leading to a vertical velocity at impact. The horizontal velocity remains constant at 18.0 m/s. Ultimately, the stone impacts the beach with a specific speed and angle derived from these calculations.

Oct 18, 2007

Cowtipper

I am not having any luck with the following question. Please help...

A stone is thrown horizontally over the edge of a cliff with a speed of 18.0 m/s. The cliff is 50.0 m above a flat beach. With what speed and angle of impact does the stone land?

Physics news on Phys.org

Oct 18, 2007

Cowtipper

I got it, never mind.

Thread 'I've come across another fluid pressure problem I don't understand'

Neglect gravity other than that of water; neglect friction. F1=ρgsh=1000*10*1*(1+4)=50000 N; F1=ρgsh=1000*10*0.1*4=4000 N; F3=50000-4000=46000 N?

View full post »

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

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...

View full post »

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}...

View full post »