Answer:
D. Time t = 1 [s]
Explanation:
To solve this problem we must use the following equation of kinematics.
where:
Vf = final velocity = 0 (when the ball reaches the maximum height its elevation won't be increased since the velocity is zero)
vi = initial velocity = 10 [m/s]
g = gravity acceleration = 10 [m/s²]
t = time [s]
Now replacing:
Answer:
F = 20 N
Explanation:
Given that,
Mass of the football, m = 2 kg
Initial speed, u = 0
Final speed,v = 5 m/s
The time of contact, t = 0.5 s
We need to found the average force applied by the footballer on the football. We can find it using the formula.
So, the required force is 20 N.
Answer:
In both cases the height is greater than 10.3 m
Explanation:
Pressure is defined by the relationship
P = F / A
in this case the force is the weight of the two gases
F = W = m g
If we use the definition of density
ρ = m / V
V = A h
m = ρ A h
we substitute
P = ρ g h
h =
For this case the density of the gases is
ρ' = 0.9
h =
we calculate
ρ’= 0.9 \rho_{water}
h = 1 105 / (0.9 1000 9.8)
h = 11.3 m
ρ’= 0.8 \rho_{water}
h = 1 105 / (0.8 1000 9.8
h = 12.8 m
In both cases the height is greater than 10.3 m