Answer:
12.68 m/s.
Explanation:
Equations of motion:
i. S = vi*t + 1/2 * a*(t^2)
ii. vf = vi + a*t
iii. vf^2 = vi^2 + 2a*S
Where, vf = final velocity
vi = initial velocity
S = distance travelled
a = acceleration due to gravity
t = time taken
Given:
vi = 0 m/s
S = 8.2 m
vf = ?
a = 9.81 m/s^2
Using iii. Equation of motion,
vf^2 = vi^2 + 2a*S
= 2 * 9.81 * 8.2
= 160.884
vf = sqrt (160.884)
= 12.68 m/s.
Answer:
efficiency = useful energy out ÷ total energy in (for a decimal efficiency)
or.
efficiency = (useful energy out ÷ total energy in) × 100 (for a percentage efficiency)
Explanation:
Answer:
Volume of the wood = 120.615 cm3
Density of the wood = 0.457 g/cm3
Explanation:
By definition, density is the mass of a substance per unit volume and its units are kg/m3, g/l etc.
Volume of a cuboid = length * breadth * height
Length = 8.5 cm
Breadth = 3.3 cm
Height = 4.3 cm
Volume of the wood = 8.5 * 3.3 * 4.3
= 120.615 cm3
Mass of the wood = 55.120 g
Density = mass/volume
= 55.120/120.615
= 0.457 g/cm3
= 457 kg/m3