Explanation:
(a) Displacement of an object is the shortest path covered by it.
In this problem, a student is biking to school. She travels 0.7 km north, then realizes something has fallen out of her bag. She travels 0.3 km south to retrieve her item. She then travels 0.4 mi north to arrive at school.
0.4 miles = 0.64 km
displacement = 0.7-0.3+0.64 = 1.04 km
(b) Average velocity = total displacement/total time
t = 15 min = 0.25 hour

Hence, this is the required solution.
Answer:
it is chemical reactivity (D)
Explanation:
it is because chemical properties are properties that can be measured and observed only when matter undergoes a change to become an entirely different kind of matter.Which they include Chemical reactivity,flammable,and the ability to rust.And Chemical reactivity is the ability of matter to react chemically with other substances.
Answer: The person sitting in the middle of the train sees the back of the train enter ing the tunnel before the front end comes out.
Explanation:
Answer:
1.23 m/s²
Explanation:
Given:
v₀ = 0 m/s
v = 11.1 m/s
t = 9 s
Find: a
Equation:
v = at + v₀
Plug in:
11.1 m/s = a (9 s) + 0 m/s
a = 1.23 m/s²
The runner's acceleration is 1.23 m/s².
Simple machines make work easier by multiplying, reducing, or changing the direction of a force. The scientific formula for work is w = f x d, or, work is equal to force multiplied by distance. Simple machines cannot change the amount of work done, but they can reduce the effort force that is required to do the work
-Matt