Answer: 0.55 m/s
Explanation:
This situation is related to projectile motion (also called parabolic motion), where the main equations are as follows:
(1)
(2)
Where:
is the horizontal displacement of the pencil
is the pencil's initial velocity
since we are told the pencil rolls <u>horizontally</u> before falling
is the time since the pencil falls until it hits the ground
is the initial height of the pencil
is the final height of the pencil (when it finally hits the ground)
is the acceleration due gravity, always acting vertically downwards
Begining with (1):
(3)
(4)
Finding from (2):
(5)
(6)
Substituting (6) in (4):
(7)
Isolating :
(8)
(9)
Finally:
A substance made up of only one type of element
Answer:
Buttery popcorn contained in a large 1 liter bowl has a mass of about 50 mg and about 650 calories.
Explanation:
Liter is the most appropriate unit to measure a bowl. Usually 1 liter of liquid has a mass of 1000 gram. Since popcorn is something lightweight and only a few can fill the bowl quickly so 50 mg makes perfect sense with 1 liter of bowl and 650 calories in buttery popcorn.
Answer:
A book on its side exerts a greater force.
Explanation:
Pressure = Force / Area
Assuming that 1kg = 10N
2kg = 20N
Area of book lying flat = 0.3m × 0.2m
= 0.6m²
Pressure of book lying flat = 20N / 0.6m²
= 30Pa (1 s.f.)
Area of book on its side = 0.2m × 0.05m
= 0.01m²
Pressure of book on its side = 20N / 0.01m²
= 2000Pa (1 s.f.)
Since 2000Pa (1 s.f.) > 30Pa (1 s.f.), a book on its side applies greater pressure than lying flat.
