Physics exam 1 study guide

A ball is thrown from the ground into the air. At a height of 9.1 m, the velocity is first observed to be v = 7.6 i +6.1 j m/s where the +x axis is to the right and the +y axis is vertically up. a) Find the position vector, r(t), and the velocity vector, v(t), using an origin at the point where it is first observed. b) To what maximum height will the ball rise? c) What will be the total horizontal distance traveled by the ball? d) What is the velocity of the ball (magnitude and direction) the instant before it hits the ground?

4p3 on hw

Antartica is roughy semicircular in shape with a radius of 2000 km. The average thickness of the ice cover is 3000m. How many cubic centimeters of ice does Antartica contain? Ignore the curvature of the Earth.

as shown

a) Two 10‐lb weights are attached to a spring scale as shown in the first figure. a) What is the reading on the spring scale? b) A single 10‐lb weight is attached to a spring scale that itself is attached to a wall as shown in the second figure. What is the reading of the scale? Note: In both cases the spring scales read the tension in the cord. c) In the first case, what will the spring scale reading be if the 10 lb weight on the right is replaced with a 15 lb weight?

c) One must use the 2nd Law to find the tension T since the system now is not in equilibrium.

A ball rolls off the top of a stairway with a horizontal velocity of magnitude 5 ft/s. The steps are 8 in. high are 8 in. wide. Which step will the ball hit first?

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A certain brand of house paint claims a coverage of 460 ft2/gal. a ) Express this quantity in square meters per liter. b) Express this quantity in SI units. c) What is the inverse of this quantity and what is its significance?

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The position of a particle moving along. the x axis dependson the time according to the equation: x(t) = at2 - bt3, where x is in ft and t in seconds. a) What dimensions and units must a and b have? For the following let their numerical values be 3.0 and 1.0, respectively. b) At what time does the particle reach its maximum positive x position? c) What total distance does the particle cover in the first 4 seconds. d) What is its displacement during the first 4 seconds? e) What is the particle's velocity at the end of eace first 4 s? f) What is the particle's acceleration at the end of eace first 4 s?

Note: average velocity = Δx/Δt = [x(tf) - x(ti)]/(tf - ti) whereas average speed = total distance/total time. Between t = 0 to t =1: average velocity = [x(1) - x(0)]/1 = (2-0)/1 = 2 ft/s; average speed = 2 later/1 = 2 ft/s Between t = 0 to t =2: average velocity = [x(2) - x(0)]/2 = (4-0)/2 = 2 ft/s; average speed = 4/2 = 2 ft/s Between t = 0 to t =3: average velocity = [x(3) - x(0)]/3 = (0-0)/3 = 0 ft/s; average speed = (4+4)/3 = 2.67 ft/s Between t = 0 to t =4: average velocity = [x(4) - x(0)]/4 = (-16 -0)/4 = -4 ft/s; average speed = (4+4+16)/4 = 6 ft/s