Complete Question:
One simple model for a person running the 100 m dash is to assume the sprinter runs with constant acceleration until reaching top speed, then maintains that speed through the finish line. If a sprinter reaches his top speed of 11.5 m/s in 2.24 s, what will be his total time?
Answer:
total time = 6.24 s
Explanation:
Using the equation of motion:
v = u + at
initial speed, u = 0 m/s
v = 11.5 m/s
t = 2.24 s
11.5 = 0 + 2.24a
a = 11.5/2.24
a = 5.13 m/s²
For the total time spent by the sprinter:
s = ut + 0.5at²
100 = 0.5 * 5.13 * t²
t² = 100/2.567
t² = 38.957
t = √38.957
t = 6.24 s
Answer:All balls have same velocity
Explanation:
Ball A
horizontal velocity
vertical velocity
let h be the height of building
Vertical velocity acquired by Ball A
Velocity just before hitting ground=
Ball B
launched with velocity u at angle of 45 above horizontal
horizontal velocity will remain same as there is no acceleration in that direction
vertical velocity just before hitting the floor
Final velocity before hitting ground
Ball C
horizontal velocity will remain same as there is no acceleration in that direction
vertical velocity just before hitting the floor
Final velocity before hitting ground
Thus all three balls will have same final velocity.
A frame of reference (or reference frame) consists of an abstract coordinate system and the set of physical reference points that uniquely locate and orient the coordinate system and standardize measurements.
It is a physical concept related to an observer and the observer's state of motion.
In n dimensions, n+1 reference points are sufficient to fully define a reference frame.
Answer:
The expression for the initial speed of the fired projectile is:
And the initial speed ratio for the 9.0mm/44-caliber bullet is 1.773.
Explanation:
For the expression for the initial speed of the projectile, we can separate the problem in two phases. The first one is the moment before and after the impact. The second phase is the rising of the ballistic pendulum.
First Phase: Impact
In the process of the impact, the net external forces acting in the system bullet-pendulum are null. Therefore the linear momentum remains even (Conservation of linear momentum). This means:
(1)
Second Phase: pendular movement
After the impact, there isn't any non-conservative force doing work in al the process. Therefore the mechanical energy remains constant (Conservation Of Mechanical Energy). Therefore:
(2)
The height of the pendulum respect L and θ is:
(3)
Using equations (1),(2) and (3):
(4)
The initial speed ratio for the 9.0mm/44-caliber bullet is obtained using equation (4):
Because the hamburger is still hot from the grill, the cheese melts because of that heat.