Physics Kinematics

Jasmine ngjiamin SG

Hi it's me again, I couldn't solve this question even with drawing a V-T graph....Please help! Thanks!

A stone is thrown vertically upwards at a speed of 60 m/s near the edge of the cliff and it falls to the bottom of the cliff after 20 seconds. What is the height of the cliff?

Ans: 980 m.

eagle SG

hi, is this for O levels or A levels?

The required solution method is different for both, one uses graph and the other uses kinematic equations.

Please follow the Guidelines for homework forum

Thanks.

Jasmine ngjiamin SG

Oops sorry this is for O levels...it is actually an MCQ question and I came across this question while practising.....tried solving for 2 hours but couldnt get the correct answer :(

hewhoshallnotbenamed SG

hi jasmine,

i had my Os last year and got an A2 for physics so im a reliable source! ^^

its quite simple really, its all about gravity & air resistance. every 1 second, the speed DECREASES when thrown UPWARDS. then due to gravity pull, the speed INCREASES when it goes DOWNWARDS to the bottom of the cliff.

check out the simple graph i've attached, hope it makes it more understandable for u. Graph

Jacky Woo SG

not everyone is as smart or academically inclined as you are.

ThunderFbolt SG

also, it is not about air resistance. it is about gravity, as you said later.

hewhoshallnotbenamed SG

@thunder: yup, slight mistake i made. edited.

@jack: i wasnt boasting, im just saying im still relatively clear about this topic. i apologize for ur insecurity

Jacky Woo SG

@jack: i wasnt boasting, im just saying im still relatively clear about this topic. i apologize for ur insecurity

wtf is that

hewhoshallnotbenamed SG

in simple terms, it means I'm just better than you