Practice+Answers

1) If a spaceship is traveling in a straight line way out in space (far away from any planets), will it ever slow down? Why or why not? Which of Newton’s laws explains this? No, because there are not other force, Newton’s first law says that objects in motion will stay in motion.

2) If Newton’s first law says that objects in motion will stay in motion, then why do things slow down when we push them? Because there is another force "the friccion", so the first law do no apply.

3) If a book sits on a table, the force of gravity pulls down. If there is a force on the book, why doesn’t it move? Because there is the Normal force.

4) If I can travel 100 m in 4 s, what is my velocity? v = d/tv=100m/4sv=25m/s

5) If I am driving at a velocity of 25 m/s, and I increase my velocity to 50 m/s in a period of 8 s, what is my acceleration? a = (vf-vo )/ta=(50-25 )/ 8a=25/8 m/s2a=3.125 m/s2

6) If I push on a 10 kg block with a force of 8 N, what is the acceleration? F=maa= F/ma=8/10a=0.8m/s2 7) If I push on an object with a force of 18 N, and it accelerates at a rate of 2 m/s2, what is the object’s mass?F=mam=F/am=18/2m=9kg

4) What is the difference between mass and weight? The wight = mass *gravityLa masa es una medida cuantitativa de la inercia

5) If you take an object to the Moon, will its mass be the same as it is on Earth? Will its weight be the same? the mass is the same and the weight is less in the Moon because the gravity of the moon is less than the earth.

6) Which object would accelerate more: a big one or a small one?The size do not matter the important is the mass of the object and the force that we apply in it

7) Describe Kepler’s First Law.

8) Describe Kepler’s Second Law. You can find this answer in your book.