Answer:
-5.63 m/s
Explanation:
Given:
y₀ = 1.62 m
y = 0 m
v₀ = 0 m/s
a = -9.8 m/s²
Find: v
v² = v₀² + 2a (y − y₀)
v² = (0 m/s)² + 2(-9.8 m/s²) (0 m − 1.62 m)
v = -5.63 m/s
Answer: the rider’s pedal force must be greater than friction and the force of gravity
Explanation:
This is because if the pedal force was less, you would go slower, and it is obviously not impossible to ride up a hill without increasing speed. But if the force was greater, your speed would increase.
<span>When a person lifts the block, the block has more potential energy. Therefore the person does positive work on the block.
work = m g h
work = (4.5 kg) (9.80 m/s^2) (1.2 m)
work = 52.92 joules
The person's work on the block is 52.92 joules
When the block is being raised, the force of gravity opposes the motion. Therefore the force of gravity does negative work on the block.
work = - (force) (h)
work = - m g h
work = -(4.5 kg) (9.80 m/s^2) (1.2 m)
work = -52.92 joules
The work done by the force of gravity on the block is -52.92 joules
Note that when the block is moved horizontally, the potential energy does not change. Therefore there is no work done on the block when it moves horizontally (we are assuming that the kinetic energy does not change).</span>
Answer:
Higher frequency.
Explanation:
Sound are mechanical waves that are highly dependent on matter for their propagation and transmission.
Sound travels faster through solids than it does through either liquids or gases. A student could verify this statement by measuring the time required for sound to travel a set distance through a solid, a liquid, and a gas.
Mathematically, the speed of a sound is given by the formula:
Generally, the frequency of a sound wave determines the pitch of the sound that would be heard.
A shrill sound refers to a type of sound that is typically sharp, high pitched and as such has higher frequency.
Hence, shrill sound is of higher frequency.
