Answer:A)u =4.295m/s , B)a = 29.746m/s² C) F=3,153N
Explanation:
Using the kinematic expression
v² = u² - 2as
where
u = initial velocity
v = final velocity
s = distance
g = acceleration due to gravity .
Given that he reaches a height of 0.940 m above the floor,
the final velocity = 0
Here, acceleration due to gravity is acting in opposite the initial direction of motion. So, a=-9.81 m/s.
v² = u² + 2as
0² - u² = 2 (- 9.81) × 0.940
- u² = 2 × - 9.81 × 0.920
- u² = -18.4428
cancelling the minus in both sides , we have that
u² = 18.4428
u = √18.4428
u =4.295m/s
(b) His acceleration (in m/s2) while he is straightening his legs. He goes from zero to the velocity found in part (a) in a distance of 0.310 m. m/s2
Using v² = u² + 2as
where u = initial speed of basketball player before lengthening = 0 m/s,
v = final speed of basketball player after lengthening = 4.295m/s,
a = acceleration while straightening his legs
s = distance moved during lengthening = 0.310m
v² = u² + 2as
a = (v² - u²)/2s
a = (4.29m/s)² - (0 m/s)²)/(2 × 0.310m)
a = (18.4428 m²/s² - 0 m²/s²)/(0.62 m)
a = (18.4428 m²/s²/(0.62 m)
a = 29.746m/s²
c) The force (in N) he exerts on the floor to do this, given that his mass is 106 kg. N
Force= mass x acceleration.
F = 106 kg X 29.746m/s²
F = 3,153.076 rounded to 3,153N
, to check it.