Answer:
(a) The horizontal ground reaction force 
(b) The vertical ground reaction force 
(c) The resultant ground reaction force 
Explanation:
Given
John mass , m = 65 kg
Horizontal acceleration , 
Vertical acceleration , 
(a) Using Newton's 2nd law in horizontal direction

=>
Thus the horizontal ground reaction force 
(b) Using Newton's 2nd law in vertical direction

=>
=>
Thus the vertical ground reaction force 
(c) Resultant ground reaction force is

=>
=>
Thus the resultant ground reaction force 
Answer:
- a.

- b.

- c.

Explanation:
The spacetime interval
is given by

please, be aware this is the definition for the signature ( + - - - ), for the signature (- + + + ) the spacetime interval is given by:
.
Lets work with the signature ( + - - - ), and, if needed in the other signature, we can multiply our interval by -1.
<h3>a.</h3>





so


<h3>b.</h3>





so


<h3>c.</h3>





so


The added weight of the sand puts more downward pressure on the wheels contacting the rails, which would cause the trains speed to decrease.
Answer:
<h2>Virtual image</h2>
Explanation:
<h3>
<em>Virtual</em><em> </em><em>image</em><em> </em><em>can</em><em> </em><em>be</em><em> </em><em>caught</em><em> </em><em>on</em><em> </em><em>a</em><em> </em><em>screen</em></h3>
<em>hope</em><em> </em><em>this</em><em> </em><em>helps</em><em> </em><em>you</em><em>.</em>
<em>will</em><em> </em><em>give</em><em> </em><em>the</em><em> </em><em>brainliest</em><em>!</em>
<em>follow</em><em> </em><em>~</em><em>H</em><em>i</em><em>1</em><em>3</em><em>1</em><em>5</em><em>~</em>
DNA
DNA provides the set of instructions that tell the organism how to form