<span>
The equation is h(t) = at^2 + vt + d
where a = acceleration of gravity = - 32.174 ft/sec^2
v = 25 feet/sec
d = starting height = 0
and h(t) = 0 when the ball hits the ground.
So, 0 = - 32.174t^2 + 25t + 0
You can use the quadratic formula on that if you want, or you can solve like this:
0 = - 32.174t^2 + 25t
0 = t ( -32.174t + 25)
So, one solution of that is t = 0, corresponding to the initial time when the ball is kicked.
The other time is: 25 = 32.174t
t = 25/32.174 = 0.777 seconds
or approximately 0.8 seconds.</span>
Answer:
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Explanation:
(a) 
First of all, we need to calculate the acceleration of the person, by using the following SUVAT equation:

where
v = 0 is the final velocity
u = 20.0 m/s is the initial velocity
a is the acceleration
d = 1.00 cm = 0.01 m is the displacement of the person
Solving for a,

And the average force on the person is given by

with m = 75.0 kg being the mass of the person. Substituting,

where the negative sign means the force is opposite to the direction of motion of the person.
b) 
In this case,
v = 0 is the final velocity
u = 20.0 m/s is the initial velocity
a is the acceleration
d = 15.00 cm = 0.15 m is the displacement of the person with the air bag
So the acceleration is

So the average force on the person is

16, 5 , 3 = 16+5+3= 24 + 3
So at the end put 24 + 3 cm
And put 16 for the lengths
For the value 5 and for the diving thingy 3
Answer:
Explanation:
Given that,
Mass of first car
M1= 328kg
The car is moving in positive direction of x axis with velocity
U1 = 19.1m/s
Velocity of second car
U2 = 13m/s, in the same direction as the first car..
Mass of second car
M2 = 790kg
Velocity of second car after collision
V2 = 15.1 m/s
Velocity of first car after collision
V1 =?
This is an elastic collision,
And using the conservation of momentum principle
Momentum before collision is equal to momentum after collision
P(before) = P(after)
M1•U1 + M2•U2 = M1•V1 + M2•V2
328 × 19.1 + 790 × 13 = 328 × V1 + 790 × 15.1
16534.8 = 328•V1 + 11929
328•V1 = 16534.8—11929
328•V1 = 4605.8
V1 = 4605.8/328
V1 = 14.04 m/s
The velocity of the first car after collision is 14.04 m/s