---

This sheet provides the answers to the questions on the review, but not the full solutions. Please come to class for the full solutions.

Exercises:

1) Vectors: Displacement, Velocity, Force, Acceleration, Momentum

Scalars: Time, Mass, Density, Volume, Temperature, Energy

2)

• Distance--How far from place to place, d, m
• Displacement--How far from a reference point, x or y, m
• Speed--The distance traveled in a certain time, s = d/t, m/s
• Velocity--The displacement traveled in a certain time, v = x/t, m/s
• Acceleration--The rate of change of velocity, a = Dv/t, m/s/s or m/s²
• Weight--The force of gravity on an object, W = mg, N
• Force--A push or a pull, F = ma, N
• Tension--Force in a Rope, T, N
• Normal Force--Contact Force, N, N
• Newton's Laws--(1) Objects in motion stay in motion if F_net=0 (2) F=ma (3) Equal and opposite forces.

3) What times m/(m/s²) gives kg (mass)? --> kg/s² or N/m

4) 497.82, 500.0 and 497.8, 498, 500. The most significant figures implies the most precise/accurate measuring device.

5) A guy goes to the corner to buy some milk, hangs out a bit, comes back and stops by a neighbor's house, passes his house and goes to another neighbor's house and stays awhile. Displacement increases, stays the same, decreases, stays the same, decreases then increases, then stays the same. The velocity is either forward or backward (depending on the slope) or zero when the displacement doesn't change.

6) The velocity starts constant (flat line, a=0) then decreases slowly (a < 0) then is constant backwards (a=0) then increase sharply (a >> 0) the is constant forwards (a = 0) and then increases again (a > 0).

7)

8) Air resistance provides a negative acceleration in the x-direction, slowing an object down and making travel less distance.

 

Problems:

1) a) 1.43 s

b) 8.57 m

c) 13.2 m

d) 9.2 m/s

e) Vx = 6 m/s, Vy = 14, --> V = 15.23 m/s, angle = 67° to horizontal

 

2) a) 539 m

b) 8.78 s

c) Vx = 61.4 m/s, Vy = 43.0 m/s x(5) = 307 m , y(5)= 92.5 m

d) after, because midpoint is at t=4.39 s

 

3) a) 3.83 m/s/s

b) 0.69 m

c) 0.391 g

d) 0.21 N

e) -0.21 N

 

4) a) 4.9 N

b) 11.78 N on each side