Answer:
cold water strengthens the magnetic attractive force.
Explanation:
The molecules within the magnet will move slower because they have less kinetic energy,so there is less vibration within the magnets molecules.
Answer:
Increasing the speed of an object decreases its motion energy. Increasing the speed of an object increases its motion energy. Increasing the speed of an object does not affect its motion energy. Whether or not its motion energy is affected depends on how much its speed was increased.
Explanation:
The magma cools very slowly so that the crystals of different minerals have time to grow. The magma molecules in have time to organize themselves into crystal formations before the magma hardens. The naked eye helps the Intrusive rocks that has large crystals be seen.
Answer:
Explanation:
Remark
At the time it takes to drop 20 m is the same time it takes to travel 60 m horizontally.
Givens
h = 20 m
hd = 60 m
g = 9.81
vi = 0
Formula
d = vi*t + 1/2 a * t^2 We are solving for t
Solution
When the battery fails, the vertical initial velocity is 0. So we have to find the time it would take to drop 20 meters
d = 0*t + 1/2 * 9.81 a* t^2
20 = 4.91 * t^2 Divide by 4.91
20/4.91 = 4.91 t^2 / 4.91
4.073 = t^2 Take the square root of both sides.
t = 2.02 seconds
Horizontal
d = 60 m
t = 2.02 seconds
v = ?
Note: there is no horizontal deceleration or acceleration
v = d/t
v = 60/2.02
Answer: v = 29.73 m/s
Answer:
Explanation:
Let v is the launch speed of the plastic ball and the angle of projection is θ.
So, in horizontal direction
v Cosθ x t = 4.8 .... (1)
In th evertical direction
1.4 = v Sin θ x t - 0.5 gt² .... (2)
As , v Sin θ x t = 3.8 .... (3) , put in equation (2)
1.4 = 3.8 - 4.9 t²
t = 0.7 s
Put in (1) and (3)
v Cosθ x 0.7 = 4.8
v Cosθ = 6.86
and v Sinθ x 0.7 = 3.8
v Sinθ = 5.43
Now
v = 8.75 m/s
