You throw a stone upward from the top of a building at an angle of 25â° to the horizontal and with an initial speed of 15 m/s. if the stone is in flight for 3.0 s, how tall is the building? how far from the base of the building does the stone.

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.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia