Ms. sullivan's class is investigating simple machines. today they are using a crowbar to lift a heavy desk. most students can lift the desk with the crowbar, even though they couldn't lift it with their bare hands.

one student in the class can't lift the desk even with the crowbar. what change should be made so the student can lift the desk?

a)
use a crowbar that is longer than the first.

b)
use a crowbar that is shorter than the first.

c)
use a crowbar that is heavier than the first.

d)
use a different type of lever that is the same length as the original crowbar.

20 point pls brianliest 1. what does a red shift mean? blue shift? 2. describe the big bang theory. according to this theory, how old is the universe? 3. scientists believe the universe is expanding. what is the evidence that supports this? 4. describe a nebula. 5. describe the 3 types of galaxies. what is a barred spiral galaxy? 6. what is a light year? how far is alpha centauri from earth? 7. describe the universal law of gravitation. be sure to include gravitational force between two objects. 8. describe the planets’ orbits around the sun. 9. what is the asteroid belt? where is it located? 10. describe rotation and revolution of earth. what determines an earth day and year? 11. how do galaxies exist? 12. compare and contrast the inner and outer planets. 13. what causes the seasons?