4) Object falls from moving object

In this lesson we do a grade 12 Vertical Projectile Motion practice question.

[Theeboydoingthingz_]

We use 1.70 sec for Stone B because it took Stone A, 6.7 sec to reach the ground. If we minus 5 sec (Because it was dropped 5 sec later) from that which is 1.7, that is the time B has been in the air for( free fall) waiting to hit the ground. (Hope it helped someone coz I struggled at first😅)

[baldiola]

For question 3.2.3 why would the time for the hot air balloon be 1, 7 seconds wasn’t the balloon was still moving before stone B was dropped and while stone A was dropping, so won’t it include those 5 seconds?

[ThaboDinga-brob]

Sir i dont understand why did you use 1.70 for the hot air ballon

[arch_dornan]

12:13 the balloon is going down, not up. The initial velocity should be positive

[Vandell-ezdu]

@Mr Kevin in 3.2.2 when calculating the time u chose downwards as positive and made V initial negative but shouldn't it be positive bcoz in 3.3.1 when we calculated that initial velocity u used downwards and got a positive answer so why'd u change pls enlighten me sir🙏🏽🙏🏽

[marywangarikaranja]

in question 3.2.2, why did you use 1.70 as the time for the hot air

[Blonded.]

sir wouldn't the time of the ballon be 5s since the ball was released at 5s so the in that 5s, the balloon should've been rising up and the 1.7s is comparison between rock B and A. when you say 1.7s for the ballon, that would mean the rock was released 1.7s later not 5?

[KelebogileSeanego]

Why do we ignore the time that stone A took when it was dropped until it reached the maximum velocity of zero and then returned downwards?...coz i think that time counts ...help me I'm confused 😢

[InamXiphu]

Why do we use 1.7 as the time for the ballon, does that mean the ballon moves after the stone hits the ground?😵‍💫

[Jususlovesall]

I was struggling at first as to why the heck we using 1.7, but then realised that they did ask how long stone B was in the air, but rather how long it was in the air at the exact moment A hit the ground, so yeah hes correct guys😂😂😂❤

[a_chan_l]

While stone A was going down the ballon was still going up. Wouldnt using 6.7s be more accurate 🤷‍♀️ I respectfully disagree with your answer Kev 14:04

[imanallie]

Why did u make the velocity of stone B a negative ?

[Hendrycandy]

Optical phenomena videos 😢 not available 💔