Answer:
Because sidewalks are usually in places where the sun can shine on them most of the day. Even if the sun can't shine directly on them, the weather can get hot. Either way, the material that the sidewalk is made of can often get hot. You know that when things heat up they "expand" ... they actually get slightly bigger. If there were no spaces in the sidewalk for it to get bigger, then when the material got hot and tried to get bigger, it would crack and break, and the whole sidewalk would be all broken up in a few months.
Answer 2
Answer:
It is because if it was one big piece, the concrete would buckle and break just like bridges.
How much force is needed to get a 0.9kg block of wood to slide if the static coefficient of friction is 0.8
Answers
0.8?? DONT know how to solve
The round pea seed trait is dominant over the wrinkled pea seed trait. If the phenotype of the pea seed is wrinkled, which combination of genes must have it? A.)Two round genes B.)One wrinkled gene only C.)Once round gene only D.)Two wrinkled genes
Answers
D. It must have two wrinkled genes. Whenever one or more of the parents' genes are dominant, the resulting daughter gene will be dominant. Thus, in order to produce a recessive gene, BOTH parent genes must be recessive as well. Because wrinkled genes are recessive, you're going to need both wrinkled genes.
I don't understand how to find the frequency and period of wavelengths. Can anyone help me?
Answers
Frequency of a wave =
(speed of the wave) divided by (wavelength) or (1) divided by (period of the wave) .
Period of the wave =
(wavelength) divided by (speed of the wave) or (1) divided by (frequency of the wave) .
A water balloon was dropped from a high window and struck its target 1.1 seconds later. If the balloon left the person's hand at -5.0 m/sec, what was its velocity on impact?
Answers
The acceleration of gravity on Earth is 9.8 meters per second every second. So in 1.1 second of falling, an object gains (9.8 x 1.1) = 10.78 meters per second of downward speed.
The balloon was already falling at 5 m/sec when the time began, and it gained another 10.78 m/sec on the way. So at the end of 1.1 second, its downward speed was (5.0 + 10.78) = 15.78 m/sec.
Its velocity was 15.78 m/sec downward.
How can you pull a rope with equal but opposite forces
Answers
You want to do it all by yourself ? Nothing to it !
Take a piece of rope that's maybe 12 to 18 inches long. Take one end of the rope in each hand, raise your hands up in front of you, and make like you're trying to stretch the rope. You'll automatically make the forces of your hands equal and opposite, so that the rope just stays there in front of you and doesn't move.
Given a force of 88N and an acceleration of 4m/s squared what is the mass?