Choose the number closest to your answer. Answer all 10 problems, and put your S

Question

Choose the number closest to your answer. Answer all 10 problems, and put your SECTION on your answer sheet. 1. A blue car traveling at 35 km/h is passed by a green car traveling at 50 km/h. At the instant it passes, the green car begins to decelerate at a constant value of -1.5 m/s How long after being passed does the blue car catch up to the green car? Assume the blue car remains at constant a) 2.18 s b) 5.56 s. c) 6.67 s d) 4.44 s e) 3.33 s 2. A bicycle, starting from rest, accelerates uniformly for 7 s, at which point it has reached a speed of 12 m/s. How far has the bicycle gone in these 7 s? a) 42.0 m b) 35.0 m c) 28.0 m d) 49.0 m e) 17.2 m 3. A 30 N force acts on an object in the 0° direction while a 50 N force acts in such a direction that the total force on the object is in the 90° direction. What is the direction of the second force? a) 139 b) 137 c) 127° d) 112 e) 104 4. An archer aims an arrow directly at a target 95 m away horizontally. If the arrow's speed is 110 m/s, at what angle should it be aimed so the target will be hit? (Remember sin 20 sin 0 cos 0.) a) 1.29 b) 1.51 c) 1.74° d) 1.97 e) 2.21 5. Two blocks are up against each other on a horizontal frictionless surface. The mass left to the is 3 kg while that to the is kg. If the left mass is pushed to the right with a force of 24 N while the right block is pushed to the left with a force of 6 N, what is the magnitude of force the that each block exerts on the other? a) 18.0 N b) 19.0 N c) 20.0 N d) 21.0 N e) 22.0 N

Explanation / Answer

1) 35 km/hr = 9.72 m/s

50 km/hr = 13.89 m/s

xblue = 9.72 t

x green = vt + 1/2 a t^2 = 13.89 - 0.5*1.5*t^2

xblue = xgreen

9.72 t= 13.89 - 0.5*1.5*t^2

solve fort

2)

v = v0 + a t

12 = a*7

a = 12/7

x = v0t + 1/2 a t^2 = 0.5*12/7*7^2 = 0.5*12*7 = 42 m

3)

so we know x direction has to be -30N

so Fx = F cos theta
-30 = 50 cos theta

theta = arcos(-30/50)

4) so use that R = v^2 sin(2theta)/g

95 = 110^2*sin(2*theta)/9.81

solve for theta

5)

so Fnet = (6+3) a

24-6 = 9 a

18 = 9 a

so a = 2

then for left block

24 - F = 3*a = 3*2

F = 24 -6 = 18 N

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---