Answer:
b. -1.5 m/s²
Explanation:
Given the following data;
Initial velocity = 15m/s
Time = 10 seconds.
Since the car came to rest, final velocity = 0m/s
To find acceleration;
In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.
This simply means that, acceleration is given by the subtraction of final speed from the initial speed all over time.
Mathematically, acceleration is given by the equation;
Where,
a is acceleration measured in 
v and u is initial and final speed respectively, measured in 
t is time measured in seconds.
Substituting into the equation, we have;
Acceleration = -1.5 m/s²
You need to divide the motion into its component: vertical and horizontal motion.
The time taken to fall vertically from the cliff is equal to the time taken to move horizontally.
Using the vertical component, which is an accelerated motion with an initial velocity equal to zero, we can solve for t:
h = 1/2 · g · t²
t = √(2·h / g)
= √(2·50 / 9.8)
= 3.2 s
Horizontally, it is a constant motion:
d = v · t
= 20 · 3.2
= 64 m
The ball will strike the ground at a distance of 64 meters from the cliff.
Answer:
A leaf is falling from the tree.
Explanation:
If motion is in only one direction(x-direction) then it is know as one directional motion.
If motion is in only two direction (x and y directions) then it is know as two directional motion.
If motion is in only three direction (x , y and z directions) then it is know as three directional motion.
A bird is flying in the air -This is three directional motion.
A leaf is falling from the tree - This is two directional motion.
A train is running on track - This is one directional motion
A lady is crawling on the surface of the ball - This is three directional motion.
Therefore the answer is ---
A leaf is falling from the tree.
The magnitudes of his q and ∆H for the copper trial would be lower than the aluminum trial.
The given parameters;
- <em>initial temperature of metals, = </em>
<em /> - <em>initial temperature of water, = </em>
<em> </em> - <em>specific heat capacity of copper, </em>
<em> = 0.385 J/g.K</em> - <em>specific heat capacity of aluminum, </em>
= 0.9 J/g.K - <em>both metals have equal mass = m</em>
The quantity of heat transferred by each metal is calculated as follows;
Q = mcΔt
<em>For</em><em> copper metal</em><em>, the quantity of heat transferred is calculated as</em>;
<em>The </em><em>change</em><em> in </em><em>heat </em><em>energy for </em><em>copper metal</em>;
<em>For </em><em>aluminum metal</em><em>, the quantity of heat transferred is calculated as</em>;
<em>The </em><em>change</em><em> in </em><em>heat </em><em>energy for </em><em>aluminum metal </em><em>;</em>
Thus, we can conclude that the magnitudes of his q and ∆H for the copper trial would be lower than the aluminum trial.
Learn more here:brainly.com/question/15345295
Answer: Larmor suggested in 1919 that a self-exciting dynamo could explain the magnetic field of the earth, as well as that of the sun and other stars, but it was Elsasser and Bullard in the 1940s who showed how motion in the liquid core of the earth might produce a self-sustaining magnetic field. By this time seismology and other studies had given a clearer picture of the earth, as having a solid inner core, a liquid outer core, both with a composition more of metal (mainly iron) than rock, and a rocky mantle, all below a thin crust that is all we can directly see. Energy from radioactivity travels outwards as heat, producing thermal convection in the core. It seems that this convection is the cause of the earth's magnetic field, although our knowledge of the core and its dynamics is sketchy. Our knowledge is limited to saying that flow regimes like those that may be occurring in the core can produce self-sustaining dynamos, with characteristics similar to that needed to produce the earth’s magnetic field.
Explanation:
