Answer:
11.025 m
87.75 m
Explanation:
Time of flight(T) of a projectile = 2U(sin∅)/g
Where U = initial Velocity, g = acceleration due to gravity, ∅= angle of projection.
Make ∅ the subject of the the equation,
∅ = sin⁻¹[(T× g)/2U]
Where U = 15m/s, T= 3.0 s, g = 9.8 m/s²
∅ = sin⁻¹[(3 × 9.8)/(2×15)]
∅ = sin⁻¹(29.4/30)
∅= sin⁻¹(0.98) = 78.52°
Using the formula for maximum height of a projectile
H = U²sin²∅/2g
H = 15²(sin²78.52)/2 × 9.8
H = 225(0.98 × 0.98)/19.6
H = 216.09/19.6
H = 11.025 m
Range (R) = U²sin2∅/g
R = 15²sin(2×79.52)/9.8
R = 225(0.39)
R =87.75 m
∵ the building is = 11.025 m tall and the base of the building is 87.75m away from where the stone landed.
The maximum height is reached when the vertical component of the velocity is zero.
vertical direction:
acceleration: a = -g = -9.81m/s²
velocity: v = -g*t + v₀
position: y = -0.5*g*t² + v₀*t + y₀
For v= 0:
0 = -g*t + v₀ => t = v₀/g
Insert into position equation gives:
y(max) = (-0.5*v₀²/g) + (v₀²/g) + y₀ = (0.5*v₀²/g) + y₀
Answer:
C
Explanation:
this is because of gravity
Answer:
SKID
Explanation:
In general, airplane tracks are flat, they do not have cant, consequently the friction force is what keeps the bicycle in the circle.
Let's use Newton's second law, let's set a reference frame with the horizontal x-axis and the vertical y-axis.
Y axis y
N- W = 0
N = W
X axis (radial)
fr = m a
the acceleration in the curve is centripetal
a =
the friction force has the expression
fr = μ N
we substitute
μ mg = m v²/r
v =
we calculate
v =
v = 1,715 m / s
to compare with the cyclist's speed let's reduce to the SI system
v₀ = 18 km / h (1000 m / 1 km) (1 h / 3600 s) = 5 m / s
We can see that the speed that the cyclist is carrying is greater than the speed that the curve can take, therefore the cyclist will SKID