The speed of an object can be determined from the distance vs time graph.
You know that speed = distance/time
in the graph, distance/time = slope of the curve.
So SPEED IS GIVEN BY THE SLOPE of the curve in the graph.
● If the distance vs time curve is a straight line, parallel to time axis(x-axis), slope is 0. That means speed is 0. So the object is at rest.
● If the distance vs time curve is a straight line, with some non-zero slope; That means speed is nonzero and constant. So the object is in uniform motion.
● If the distance vs time curve is a curved, the slope is changing. That means speed is changing. So the object is in an accelerated motion.
Answer:
when the old wooden stiff poles were being used, none of the kinetic energy during the run-up was stored in the pole. With the new fiber glass flexible pole, some of that energy is stored in the flexing of the pole and then released as the pole straightens out at the top of its arc. Where 13 ft was considered an excellent competition vault with the stiff pole, the additional boost from the stored energy in the flex pole has made 17 ft vaults the winning heights.
Explanation:
when the old wooden stiff poles were being used, none of the kinetic energy during the run-up was stored in the pole. With the new fiber glass flexible pole, some of that energy is stored in the flexing of the pole and then released as the pole straightens out at the top of its arc. Where 13 ft was considered an excellent competition vault with the stiff pole, the additional boost from the stored energy in the flex pole has made 17 ft vaults the winning heights.
The flexible fiberglass poles can bend more than wooden ones, before breaking. This meant that fiberglass poles are able to store more energy than wooden ones, and provide an additional increase in height to the vaulter, when the pole straightens out near the top of the vault.
Тнe Anѕwer
-It was Ernest Rutherford
Here in order to find out the distance between two planes after 3 hours can be calculated by the concept of relative velocity
here
speed of first plane is 700 mi/h at 31.3 degree
speed of second plane is 570 mi/h at 134 degree
now the relative velocity is given as
now the distance between them is given as
so the magnitude of the distance is given as
miles
so the distance between them is 2985.6 miles
Answer:
-0.4D(maybe)
Explanation:
combined focal length (f)= 0.4m
D1 = 5D
Then f1= 1/D1
= 1/5 = 0.2 m
1/f=1/f1+1/f2
1/0.4=1/0.2+1/f2
f2= -5/2
D2=1/f2= -0.4D