00:01
Have a block at the top of a frictionless ramp two meters long and point block takes 2 .5 seconds to travel 1 .8 meters down the ramp.
00:15
We're asked some questions about the acceleration and gravity.
00:23
So let's use this coordinate system.
00:34
Along the ramp is x and perpendicular to the ramp is y.
00:39
Okay, and this is theta right here on the ramp i forgot to draw that.
00:48
So let's just start with question a.
00:58
What is the value of sine theta? so sine theta is opposite over hypotenuse or 0 .1 meters over 2 meters.
01:19
So sine theta equals 0 .05.
01:34
What is the magnitude of the acceleration in the x direction.
01:51
I'm trying to solve for the acceleration in the x direction.
01:55
So let's use a kinemic equation here.
01:57
That x final equals x initial plus velocity initial in the x direction times time plus one half acceleration in the x times time squared.
02:16
And let's just call the initial position x equals zero.
02:20
You know that it has no initial velocity.
02:22
So if we say x final is 1 .8 meters.
02:27
So that's the distance that travels down the ramp.
02:31
And give us that time equals two and a half seconds.
02:39
So let's solve for acceleration here.
02:41
So a x is then equal to two x final over time squared, which is 0, 7, 6 meters per second squared.
03:16
Now part c, we're supposed to calculate the value for the gravitational constant g...