Answer:
vb = 22.13 m/s
So, the only thing that was measured here was the height of point A relative to point B. And the Law of Conservation of Energy was used.
Explanation:
In order to find the speed of roller coaster at Point B, we will use the law of conservation of Energy. In this situation, the law of conservation of energy states that:
K.E at A + P.E at A = K.E at B + P.E at B
(1/2)mvₐ² + mghₐ = (1/2)m(vb)² + mg(hb)
(1/2)vₙ² + ghₐ = (1/2)(vb)² + g(hb)
where,
vₙ = velocity of roller coaster at point a = 0 m/s
hₙ = height of roller coaster at point a = 25 m
g = 9.8 m/s²
vb = velocity of roller coaster at point B = ?
hb = Height of Point B = 0 m (since, point is the reference point)
Therefore,
(1/2)(0 m/s)² + (9.8 m/s²)(25 m) = (1/2)(vb)² + (9.8 m/s²)(0 m)
245 m²/s² * 2 = vb²
vb = √(490 m²/s²)
<u>vb = 22.13 m/s</u>
<u>So, the only thing that was measured here was the height of point A relative to point B. And the Law of Conservation of Energy was used.</u>
Answer:
43.7 °C
Explanation:
= Coefficient of linear expansion of brass = 
= Coefficient of linear expansion of steel = 
= Initial length of brass = 31 cm
= Initial length of steel = 11 m
= Total change in length = 3 mm
Total change in length would be


The final temperature is 43.7 °C
Answer:
If you throw a pebble into a pond, ripples
spread out from where it went in. These
ripples are waves travelling through the
water. The waves move with a transverse
motion.
Explanation:
I think the logical question here is to either find the distance or the displacement. They differ in such a way that distance is a scalar quantity that does not focus on the direction. Displacement is a vector quantity that covers the distance from the starting point to end point. Because it travels only in one direction (to the east), in this condition, distance is equal to displacement.
Distance = Displacement = 3,000 m + 1,500 m = 4,500 m
Answer: 2700 Joules
Explanation:
Given variables are:
Workdone (w) = ?
Weight of sack (w) = 15N
Time taken (t) = 3 minutes
The standard unit of time is seconds, so convert 3 minutes to seconds
(If 1 minute = 60 seconds
3 minutes = 3 x 60 = 180 seconds)
Recall that work is done is when force is applied on an object over a distance
i.e Workdone = force x distance.
(However, the force acting on the sack of potatoes is weight)
Hence, workdone = weight x time
w = 15N x 180 seconds
w = 2700 J
thus, 2700 joules of work was done.