This is an example of free fall;
For free fall the gravitational acceleration is -9.8 m/s²
From the equation;
S = ut -1/2gt², where S is the height above the ground, U is the initial vertical velocity, t is the time taken.
Therefore;
1.2 = 20t - 1/2(9.8)t²
1.2 = 20t -4.9t²
Thus; the equation is -4.9t² + 20t = 1.2, this is the appropriate answer.
Answer:
Evidence for continental drift
Wegener knew that fossil plants and animals such as mesosaurs, a freshwater reptile found only South America and Africa during the Permian period, could be found on many continents. He also matched up rocks on either side of the Atlantic Ocean like puzzle pieces.
Explanation:
Answer:
d = 25.51 m
Explanation:
the law of the conservation of energy says that:
where is the inicial energy, is the final energy and is the work of the friction.
so:
=
where M is the mass and V the velocity.
also,
where is the coefficient of kinetic frictio, N is the normal force and d is the distance.
therefore:
also, N is equal to the mass of the hockey puck multiplicated by the gravity.
replacing:
canceling the m:
solving for d:
d = 25.51 m
Answer: Atomic number, Atomic Mass, Ionic radius
Explanation:
Answer:
Contraction of Chicago concrete walkway = 8.64 x 10⁻³ m
Explanation:
Thermal expansion or compression is given by ΔL = LαΔT
Here Length of Chicago concrete walkway, L = 18 m
Change in temperature, ΔT = (-16 - 24) = -40 °C
Coefficient of thermal expansion for concrete, α = 12 x 10⁻⁶ °C⁻¹
Substituting
ΔL = LαΔT = 18 x 12 x 10⁻⁶ x (-40) = -8.64 x 10⁻³ m
Contraction of Chicago concrete walkway = 8.64 x 10⁻³ m