physics 1 final

a box is being pulled up a rough incline by a rope connected to a pulley. how many forces are doing work on the box

3 forces

.00325 x 10^-8 cm can also be expressed in mm as?

3.52x10^-10 mm

you drive for 30 minutes at 30 mi/hr and then for another 30 minutes at 50 mi/hr. what is your average speed for the whole trip

40 mi/hr

where is center of mass of a baseball bat located

closer to the thick end

a child on a skateboard is moving at a speed of 2 m/s after a force acts on the child, her speed is 3 m/s what can you say about the work done by external force on the child

positive work was done

2 paths lead to the top of a big hill. one is steep and direct, while the other is twice as long but less steep. how much more potential energy would you gain if you take the longer path

the same

you throw a ball upward with an initial speed of 10 m/s assuming that there is no air resistance what is its speed when it returns to you

10 m/s

the moon does not crash into earth because

its in earths gravitational field

you lift a book with your hand in such a way that it moves up at constant speed. while it is moving what is the total work done on the book

zero

What is the value of pi(8.104)^2

206.3

you are adding vectors of length 20 and 40 units. what is the only possible resultant magnitude that you can obtain out of the following choices

37

a box slides with initial velocity 10 m/s on a frictionless surface and collides inelastically with an identical box. the boxes stick together after the collision. what is the final velocity

5 m/s

you swing a ball at the end of the a string in a vertical circle. since the ball is in circular motion there has to be a centripetal force. at the top of the balls path what is the centripetal force equal to

Fc= T+mg

which of the following graphs represent an object at rest

a horizontal straight line

a space station revolves around the earth as a satellite, 100 km above earth's surface. what is the net force on an astronaut at rest inside the space station

a little less than her weight on earth

by what factor does the kinetic energy of a car change when its speed is doubled

factor of 4

you drive your dad's car too fast around a curve and the car starts to skid. what is the correct description of the situation

friction between tires and road is not strong enough to keep car in a circle

if each component of a vector is doubled, what happens to the angle of that vector

it does not change

when a bullet is fired from a gun the bullet and the gun have equal and opposite momenta. if this is true then why is the bullet deadly

it has more kinetic energy than the gun

the graph of position versus time for a car is given below. what can you say about the velocity of the car over time

it moves at constant velocity

if the position of a car is zero,

its speed does not have to be zero

a rider in a barrel of fun finds herself stuck with her back to the wall. which diagram correctly shows the forces acting on her

one line horizontal to the left, one north and one south

if the distance to the moon were doubled then the force of attraction between earth and the moon would be

one quarter

you revolve a ball around you in a horizontal circle at constant speed on a string as shown in the figure. which path will the ball take if you let go of the string when the ball is at point P

straight horizontal line to the right

two equal mass rocks tied to strings are whirled in horizontal circles. the radius of circle 2 is twice that of circle 1. if the period of motion is the same for both rocks, what is the tension in cord 2 compared to cord 1

t2=2 T1

a ball tired to a string is being whirled around in a circle. what can you say about the work done by tension

tension does no work at all

a small car and a large truck collide head-on and stick together. which one has the larger momentum change

they both have the same momentum change

according to newton's universal law of gravity, earth pulls the moon, and the moon pulls the earth, which pull is stronger

they pull on each other equally

when throwing a ball straight up, which of the following is true about its velocity v and its acceleration a at the highest point in its path

v=0, but a may not be equal to 0

you are a passenger in a car not wearing a seat belt the car makes a sharp left turn from your perspective in the car what do you feel is happening to you

you are thrown to the right