physics homework 2
DESCRIPTION
PHYS 101/Spring 2014 / HW 2 Due Thu, Jan 28 NAME Sect 1) (3 points) Mark the following as Vector (V) or Scalar (S) mass ____S______ force ____V______ speed ____S______ 2) Fill in the table with an appropriate unit and abbreviation (or complete what has been started). There may be more than one correct answer, but only one is required for credit.Physical Quantity British Engineering BE Metric MWeight Pounds lbs Newtons NMass ////////////////////////////////////////////// //////////// Kiligrams kgvelocity Miles per hour mi/hr Meters per second m/s Fill in the blank. (4 points)3) To completely describe a vector, this includes both its magnitude and its direction .4) What is the measure of inertia? Mass5) An object moving at constant velocity is in dynamic equilibrium. An object at rest (not moving) is in static equilibrium. Both of these are types of mechanical equilibrium.6) An object is “accelerating” if it is speeding up or slowing down. If an object is at constant speed but in circular or curved motion, is its velocity constant? (yes/no) no________ Is this object accelerating? (yes/no) ___yes_________Numerical Response (11 points) 7) __60 mph__________ A city is 400 miles straight east of your home. To get there you travel along a 600 mile winding path, taking 10 hours. What is the car’s average speed?8) __40 mph east In question (7) above, what is the car’s average velocity? (hint: how far from the starting point did you actually finish?!!!)9) ____2 m/ss_________ If a car speeds up from 4 m/s to 20 m/s in 8-sec, what is its average acceleration? a = = (20 m/s-4 m/s)/(8 sec) = 2m/s210) A car moves with a constant velocity of 8/ m/s East for 4 seconds. 24 m a) How far does it move in the first 3 seconds? d=(8 m/s) ( 3s)=24 m 8 m b) How far does it move in the 3rd second? ( 8 m/s) (1s)=8 m 8 m/s c) How fast is it moving at the end of the 3rd second? = 0 m/ss d) What is its acceleration at the end of the 3rd second?11). A ball rolls down a ramp with an acceleration of 4 m/s2 with an initial velocity = 0m/s. 4 m/s a) How fast is it moving at the end of the 1st second? vf = vi + at; vf = 0 m/s + (4 m/s2 )(1s) = 4 m/s 8 m/s b) How fast is it moving at the end of the 2nd second? vf = 0m/s + (4m/s2)(2s) = 8m/s 6 m c) How far does it move during the 2nd second? v ̅t = (4m/s+8m/s)/2 x 1s = 6 m 32 m d) How far does it move in the first four seconds? d= v ̅t = ((0m/s+16m/s)/2)(4 s)=32 mFill in the appropriate boxes. 12) A ball is thrown straight up from the Earth’s surface (ignore air resistance). T F at its peak elevation, the acceleration is zero false at its peak elevation, the ball is in equilibrium false on its way up the velocity is upward true on its way up the acceleration is constant true on its way down the acceleration is increasing false on its way down the velocity is increasing true 13) A ball is thrown straight up into the air at 50 m/s. If the acceleration due to gravity is 10 m/s2 ____10 m/s__________ what is the velocity of the ball at the end of the 4th second? ____30 m/s__________ what is the average velocity of the ball through the first 4 seconds? _____5 s_________ at what time will the ball actually have velocity = 0 m/s?TRANSCRIPT
PHYS 101/Spring 2014 / HW 2 Due Thu, Jan 28NAME Sect
1) (3 points) Mark the following as Vector (V) or Scalar (S)
mass __________ force __________ speed __________
2) Fill in the table with an appropriate unit and abbreviation (or complete what has been started). There may be more than one correct answer, but only one is required for credit.
Physical QuantityBritish EngineeringBEMetricM
WeightlbsN
Mass//////////////////////////////////////////////////////////kg
velocity/hrm/s
Fill in the blank. (4 points)
3) To completely describe a vector, this includes both its magnitude and its .4) What is the measure of inertia? ________________________________5) An object moving at constant velocity is in equilibrium. An object at
rest (not moving) is in equilibrium. Both of these are types of mechanical equilibrium.
6) An object is accelerating if it is speeding up or slowing down. If an object is at constant speed but in circular or curved motion, is its velocity constant? (yes/no)________ Is this object accelerating? (yes/no) ____________
Numerical Response (11 points)
7) ____________ A city is 400 miles straight east of your home. To get there you travel along a 600 mile winding path, taking 10 hours. What is the cars average speed?
8) ____________In question (7) above, what is the cars average velocity? (hint: how far from the starting point did you actually finish?!!!)
9) _____________ If a car speeds up from 4 m/s to 20 m/s in 8-sec, what is its average acceleration?
10) A car moves with a constant velocity of 8/ m/s East for 4 seconds.
a) How far does it move in the first 3 seconds?
b) How far does it move in the 3rd second?
c) How fast is it moving at the end of the 3rd second?
d) What is its acceleration at the end of the 3rd second?
11). A ball rolls down a ramp with an acceleration of 4 m/s2 with an initial velocity = 0m/s.
a) How fast is it moving at the end of the 1st second?
b) How fast is it moving at the end of the 2nd second?
b) How far does it move during the 2rd second?
d) How far does it move in the first four seconds?
Fill in the appropriate boxes.
12) A ball is thrown straight up from the Earths surface (ignore air resistance).TFat its peak elevation, the acceleration is zeroat its peak elevation, the ball is in equilibriumon its way up the velocity is upwardon its way up the acceleration is constanton its way down the acceleration is increasingon its way down the velocity is increasing
13) A ball is thrown straight up into the air at 50 m/s. If the acceleration due to gravity is 10 m/s2
a) ______________ what is the velocity of the ball at the end of the 4th second?
b) ______________ what is the average velocity of the ball through the first 4 seconds?
c) ______________ at what time will the ball actually have velocity = 0 m/s?1