I don't know if it makes a difference, but 9.8 isn't the rate of descent. It's the acceleration due to gravity, in m per second squared, but it would be approximately the same if the descent is only for about one second.
@Truthcat, You are right, if you do the math right he only needs to be going 44 kmph and that’s assuming he just jumped straight out. If he jumped slightly up and out he could cover the same distance at a slower speed.
@Truthcat, He never even calculated angular velocity for example jumping off at a 45° angle I think we was just doing straight off which would give you an increasing lower number, if I was the Rock I’d jump not just run straight off. However from the Picture It does look like he just ran off
@Truthcat, 9.8 is the change in velocity per second. The correct answer (assuming he ran straight out) is the square root of (7.4/4.9) or 1.23 seconds. So he'd need a horizontal velocity of 12.2 m/s (27.3 mph). If you assume he jumped up(and I can't imagine anybody not trying
to jump up) at an average jump velocity of 1.5 m/s, then it takes 1.39 seconds to fall 7.4 meters, requiring a horizontal speed of 10.79 m/s, or 24.1 mpg. I assume the rock could jump a little faster than average, so required speed would be even less.
@occasionalmutant, upvote for physics.
@Wallace R West, angular velocity has nothing to do with linearly moving objects. It only has to do with spinning objects like wheels and disks, also if I'm gunna get really accurate here, angular velocity isn't really a thing at all. It's a generalized term that people outside the engineering field use to describe the concept of linear and tangential velocity.
@Gadget, angular velocity is a thing. It is symbolized by Omega, where omega = 2pi*frequency. It is the rate of change of angular displacement. If an object swings through 90 degrees in one second, then its angular velocity is pi/2 radians per second. On object one meter from the
@occasionalmutant, yes but like I said omega is just another way of describing the linear and tangential velocity. Linear velocity = w/r
@occasionalmutant, an object one meter from the center has the same angular velocity as an object 10 meters from the center - they are both going through 90 degrees in one second. But the object further away has a faster linear velocity. The linear velocity is the distance from the center multiplied by the angular velicity
@Truthcat, it makes a huge difference. If his jump is average he can be going as slow as 35kph which is still slightly higher than average but I bet the rock can do it.
@Gadget, centripetal force for the win Alex!
@Will I Am Shat nerd, if you would have said cetrifugal force I would have murdered you. As it stands, my physics friend next to me still wants to murder you, that term is for plebs he says.
@Gadget, yes it is, first year engineering stuff, but how many on fp know that much?
@Will I Am Shat nerd, hardly anyone anymore, but I'm very pleasantly suprised on occasion when I see upper level calculus based physics being done in the comments section. (Even though sometimes it's very wrong)
@Gadget, just whip out that derivative and blind them with it. No need to go triple integral , three dimensional, with wind speed and turn them into mental jello.
@Will I Am Shat nerd, I'm personally a fan of mixing 3 sets of classes together when I wanna blind people. I mix Fluids 2 (aerodynamics) with Heat Transfer/Thermodynamics, and then I hit em in the face with the upper level advanced dynamics and vibrations. If you add all the portions of those classes to cover all sides of a physics problem and the energy contained within the reactions, people lose their minds.
@Gadget, best single class for me was in System Design when the PhD teacher spent the entire period and wrote out the equation for geopositioning of a stationary satellite with correcting protocols. The guy publishes a couple of times a year correcting JPL'S articles.
Loved thermo class, btw.
@Will I Am Shat nerd, my calc teacher about 5 years ago now, was so fast at mental math that he could outperform your calculator out to 6-8 decimal places and he was faster than you could type it in. It was insane, the guy was hella smart.
@Will I Am Shat nerd, she blinded me, with science!
@Jakespeare, All my tubes and wires
And careful notes!
@Truthcat, we’re gonna have to science the shjt out of this
@Wallace R West, in the trailer he does jump slightly if this helps at all
But let’s be real...as if The Rock couldn’t make that jump. That man can do anything!
@Kazza9, the engineer in me loves that some fellow nerd sat down to figure this out. The rock fan in me says fvck you. The rock can do anything
@Kazza9, Can he stop being awesome?
I think this person forgot that jumping is a thing and it adds height
@Davrial, yeah. I’m not sure they accounted for the upwards arc of jumping as well.
@Davrial, I have never seen anyone jump up 20ft...about the additional height usain would have needed on his best day. But why fight over a stupid movie
@The mortiest morty, jumping can also propel you forward more than simply running would
@The mortiest morty, they also have longer than .75 seconds because they mathed acceleration wrong. Didn't account for a vertical arc. Not did they account the extra 7ish ft he gets by catching it with his hands as opposed to landing. I think he could more reasonably make it with those included.
@The mortiest morty, did you just ask why we should fight over a stupid movie? I mean... are you new here?!? We fight over everything. Welcome to funny pics. :-)
Are you saying that this movie is not realistic? Shocking...
Gravity doesnt make things fall at 9.8m/s it makes them accelerate at 9.8m/s^2
So, what you’re saying is, Usain Bolt wouldn’t make the jump??
It seems like the entire picture is based in the measurement of the Rock as the baseline for the size of a pixel, but the rock is not standing straight up, he is hunched over during a jump. His height there might only be 5 ft 6 or 5 ft 4. That changes the measurements of the rest of this picture. The shot was also taken from below, possibly distorting the image. Gravity also doesn’t work the way this picture states. After 1 second he would only have fallen about 4.9 meters
@Univofga01, dammit I didn’t see you beat me to calling that out before I posted lol
Potentiall killer here
We don’t know all the axis in the dimension so it could potentially be a larger distance at an angle
Also you have to account for the natural distortion of how a camera operates because well.. they use lenses
THERE GOES MY HERO
This seems like something Neil deGrasse Tyson would post.... I'm just gonna move on with my happy day
But does he die?
Everything about this math is painfully wrong
But are you entertained?
The measuring key is wrong, The Rock isn’t standing straight up on the 6’6” part so it’s actually a shorter distance and height than guesstimated
Who said he made the jump?
Freakin cannabalt over here...
No one could make that jump, especially without a running start
This is an outrage. It's like they're abandoning their intellectual integrity for no reason at all, just to make a movie entertaining. This is a slippery slope.
There are a few steps missing out of this math to increase likeliness of successful jump. But the most important one is that he’s the mother fvcking rock.
Is it just me or is it really hard to read or understand this picture