This website contains problems from math contests. Problems and corresponding tags were obtained from the Art of Problem Solving website.

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Found problems: 4

2011 F = Ma, 5

Tags: 2011 , Problem 5
A crude approximation is that the Earth travels in a circular orbit about the Sun at constant speed, at a distance of $\text{150,000,000 km}$ from the Sun. Which of the following is the closest for the acceleration of the Earth in this orbit? (A) $\text{exactly 0 m/s}^2$ (B) $\text{0.006 m/s}^2$ (C) $\text{0.6 m/s}^2$ (D) $\text{6 m/s}^2$ (E) $\text{10 m/s}^2$

2008 F = Ma, 5

Tags: 2008 , Problem 5
Which of the following acceleration [i]vs.[/i] time graphs most closely represents the acceleration of the toy car? [asy] size(300); Label f; f.p=fontsize(8); xaxis(0,3); yaxis(-2,2); label("Time (s)",(2.8,0),0.5*N); label(rotate(90)*"Acceleration",(-0.2,0),W); label("$0$",(-0,0),SW,fontsize(9)); label("1",(1,0),2*S,fontsize(9)); label("2",(2,0),2*S,fontsize(9)); label("3",(3,0),2*S,fontsize(9)); draw((0.5,0)--(0.5,-0.1)); draw((1,0)--(1,-0.1)); draw((1.5,0)--(1.5,-0.1)); draw((2,0)--(2,-0.1)); draw((2.5,0)--(2.5,-0.1)); draw((3,0)--(3,-0.1)); label("(a)",(1.5,-2),N); pair A, B, C, D, E, F; A = (0,1); B = (1,1); C = (1,0); D = (1.5,0); E = (1.5, 0.5); F = (3, 0.5); draw(A--B--C--D--E--F); real x=6; Label f; f.p=fontsize(8); draw((x+3,0)--(x+0,0)); draw((x,-2)--(x,2)); label("Time (s)",(x+2.8,0.03),0.5*N); label(rotate(90)*"Acceleration",(x-0.2,0),W); label("$0$",(x+0,0),SW,fontsize(9)); label("1",(x+1,0),2*S,fontsize(9)); label("2",(x+2,0),2*S,fontsize(9)); label("3",(x+3,0),2*S,fontsize(9)); draw((x+0.5,0)--(x+0.5,-0.1)); draw((x+1,0)--(x+1,-0.1)); draw((x+1.5,0)--(x+1.5,-0.1)); draw((x+2,0)--(x+2,-0.1)); draw((x+2.5,0)--(x+2.5,-0.1)); draw((x+3,0)--(x+3,-0.1)); label("(b)",(x+1.5,-2),N); /*The lines*/ pair G, H, I, J, K, L; G = (x+0,1); H = (x+1,1); I = (x+1,0); J = (x+1.5,0); K = (x+1.5, -0.5); L = (x+3, -0.5); draw(G--H--I--J--K--L);[/asy][asy] size(300); Label f; f.p=fontsize(8); xaxis(0,3); yaxis(-2,2); label("Time (s)",(2.8,0),0.5*N); label(rotate(90)*"Acceleration",(-0.1,0),W); label("$0$",(-0,0),SW,fontsize(9)); label("1",(1,0),2*S,fontsize(9)); label("2",(2,0),2*S,fontsize(9)); label("3",(3,0),2*S,fontsize(9)); draw((0.5,0)--(0.5,-0.1)); draw((1,0)--(1,-0.1)); draw((1.5,0)--(1.5,-0.1)); draw((2,0)--(2,-0.1)); draw((2.5,0)--(2.5,-0.1)); draw((3,0)--(3,-0.1)); label("(c)",(1.5,-2),N); pair A, B, C, D, E, F; A = (0,0.5); B = (1,0.5); C = (1,0); D = (1.5,0); E = (1.5, -1); F = (3, -1); draw(A--B--C--D--E--F); real x = 6; Label f; f.p=fontsize(8); draw((x+3,0)--(x+0,0)); draw((x,-2)--(x,2)); label("Time (s)",(x+3.4,0),0.5*N); label(rotate(90)*"Acceleration",(x-0.2,0),W); label("$0$",(x+0,0),SW,fontsize(9)); label("1",(x+1,0),2*S,fontsize(9)); label("2",(x+2,0),2*S,fontsize(9)); label("3",(x+3,0),2*S,fontsize(9)); draw((x+0.5,0)--(x+0.5,-0.1)); draw((x+1,0)--(x+1,-0.1)); draw((x+1.5,0)--(x+1.5,-0.1)); draw((x+2,0)--(x+2,-0.1)); draw((x+2.5,0)--(x+2.5,-0.1)); draw((x+3,0)--(x+3,-0.1)); label("(d)",(x+1.5,-2),N); /*The lines*/ pair K, L, M, N, O, P, Q, R; K = (x+0,1); L = (x+1,1); M = (x+1,0.5); N= (x+1.5,0.5); O= (x+1.5, -0.5); P = (x+2.5, -0.5); Q = (x+2.5, 0.5); R = (x+3, 0.5); draw(K--L--M--N--O--P--Q--R);[/asy][asy] size(150); Label f; f.p=fontsize(8); xaxis(0,3); yaxis(-2,2); label("Time (s)",(3.2,0.03),N); label(rotate(90)*"Acceleration",(-0.1,0),W); label("$0$",(-0,0),SW,fontsize(9)); label("1",(1,0),2*S,fontsize(9)); label("2",(2,0),2*S,fontsize(9)); label("3",(3,0),2*S,fontsize(9)); draw((0.5,0)--(0.5,-0.1)); draw((1,0)--(1,-0.1)); draw((1.5,0)--(1.5,-0.1)); draw((2,0)--(2,-0.1)); draw((2.5,0)--(2.5,-0.1)); draw((3,0)--(3,-0.1)); label(rotate(90)*"Acceleration",(-0.1,0),W); label("(e)",(1.5,-2),N); /*The lines*/ pair A, B, C, D, E, F, G, H; A = (0,1); B = (1,1); C = (1,0.5); D = (1.5,0.5); E = (1.5, -0.5); F = (2.5, -0.5); G = (2.5, 0.5); H = (3, 0.5); draw(A--B--C--D--E--F--G--H); [/asy]

2010 F = Ma, 5

Tags: 2010 , Problem 5
Two projectiles are launched from a $35$ meter ledge as shown in the diagram. One is launched from a $37$ degree angle above the horizontal and the other is launched from $37$ degrees below the horizontal. Both of the launches are given the same initial speed of $v_\text{0} = \text{50 m/s}$. [asy] size(300); import graph; draw((-8,0)--(0,0)--(0,-11)--(30,-11)); draw((0,-11)--(-4.5,-11),dashdotted); draw((0,0)--(12,0),dashdotted); label(scale(0.75)*"35 m",(0,-5.5),5*W); draw((-4,-4.5)--(-4,-0.5),EndArrow(size=5)); draw((-4,-6)--(-4,-10.5),EndArrow(size=5)); // Projectiles real f(real x){ return -11x^2/49; } draw(graph(f,0,7),dashed+linewidth(1.5)); real g(real x){ return -6x^2/145+119x/145; } draw(graph(g,0,29),dashed+linewidth(1.5)); // Labels label(scale(0.75)*"Projectile 1",(20,2),E); label(scale(0.75)*"Projectile 2",(6,-7),E); [/asy] The difference in the times of flight for these two projectiles, $t_1-t_2$, is closest to (A) $\text{3 s}$ (B) $\text{5 s}$ (C) $\text{6 s}$ (D) $\text{8 s}$ (E) $\text{10 s}$

2009 F = Ma, 5

Tags: 2009 , Problem 5
Three equal mass satellites $A$, $B$, and $C$ are in coplanar orbits around a planet as shown in the figure. The magnitudes of the angular momenta of the satellites as measured about the planet are $L_A$, $L_B$, and $L_C$. Which of the following statements is correct? [asy] // Code created by riben size(250); dotfactor=12; draw(circle((0,0),1.5),linewidth(2)); draw(circle((0,0),6),dashdotted); draw(circle((0,0),14),dashed); draw(ellipse((4,0),10,8),linewidth(1)); pair A,B,C; A=(-7,12.12); B=(5,7.9); C=(5.7,-1.87); dot(A); dot(B); dot(C); label("A",A,NW*1.5); label("B",B,NW*1.5); label("C",C,E*1.5); filldraw((-1.500, 0.078)-- (-1.428, 0.080)-- (-1.337, 0.094)-- (-1.295, 0.157)-- (-1.246, 0.209)-- (-1.186, 0.227)-- (-1.143, 0.290)-- (-1.148, 0.357)-- (-1.135, 0.469)-- (-1.057, 0.505)-- (-0.996, 0.563)-- (-0.936, 0.526)-- (-0.852, 0.557)-- (-0.773, 0.587)-- (-0.772, 0.716)-- (-0.765, 0.828)-- (-0.781, 0.955)-- (-0.732, 1.035)-- (-0.648, 1.083)-- (-0.605, 1.162)-- (-0.604, 1.246)-- (-0.645, 1.295)-- (-0.736, 1.270)-- (-0.796, 1.229)-- (-0.851, 1.193)-- (-0.941, 1.135)-- (-1.014, 1.076)-- (-1.105, 0.995)-- (-1.154, 0.921)-- (-1.227, 0.841)-- (-1.288, 0.760)-- (-1.349, 0.669)-- (-1.398, 0.556)-- (-1.453, 0.465)-- (-1.485, 0.357)-- (-1.510, 0.239)--cycle,gray); filldraw((-0.119, 1.245)-- (-0.130, 1.193)-- (-0.146, 1.095)-- (-0.202, 1.056)-- (-0.327, 1.033)-- (-0.262, 1.031)-- (-0.278, 0.979)-- (-0.193, 0.949)-- (-0.108, 0.943)-- (-0.013, 0.941)-- (0.032, 0.915)-- (0.026, 0.840)-- (0.015, 0.779)-- (0.019, 0.705)-- (0.074, 0.646)-- (0.113, 0.582)-- (0.162, 0.533)-- (0.167, 0.463)-- (0.241, 0.400)-- (0.311, 0.412)-- (0.416, 0.410)-- (0.465, 0.342)-- (0.541, 0.410)-- (0.611, 0.347)-- (0.679, 0.242)-- (0.728, 0.132)-- (0.732, 0.048)-- (0.671, -0.037)-- (0.615, -0.104)-- (0.540, -0.172)-- (0.409, -0.209)-- (0.324, -0.244)-- (0.253, -0.293)-- (0.188, -0.314)-- (0.162, -0.389)-- (0.181, -0.486)-- (0.270, -0.534)-- (0.340, -0.537)-- (0.380, -0.596)-- (0.424, -0.688)-- (0.418, -0.772)-- (0.352, -0.825)-- (0.281, -0.883)-- (0.241, -0.926)-- (0.145, -0.981)-- (0.044, -1.044)-- (-0.006, -1.107)-- (-0.007, -1.190)-- (0.077, -1.216)-- (0.162, -1.213)-- (0.253, -1.163)-- (0.323, -1.128)-- (0.404, -1.075)-- (0.510, -1.015)-- (0.605, -0.980)-- (0.671, -0.931)-- (0.731, -0.920)-- (0.817, -0.852)-- (0.898, -0.798)-- (0.963, -0.777)-- (0.964, -0.708)-- (1.024, -0.645)-- (1.025, -0.571)-- (0.976, -0.488)-- (0.912, -0.425)-- (0.878, -0.347)-- (0.823, -0.289)-- (0.779, -0.225)-- (0.744, -0.193)-- (0.756, -0.100)-- (0.816, -0.033)-- (0.837, 0.047)-- (0.838, 0.122)-- (0.824, 0.200)-- (0.800, 0.307)-- (0.796, 0.381)-- (0.872, 0.416)-- (0.967, 0.414)-- (1.016, 0.360)-- (1.096, 0.381)-- (1.117, 0.428)-- (1.058, 0.506)-- (0.998, 0.564)-- (0.954, 0.591)-- (0.914, 0.617)-- (0.860, 0.676)-- (0.800, 0.716)-- (0.751, 0.775)-- (0.757, 0.859)-- (0.797, 0.921)-- (0.823, 0.987)-- (0.889, 1.096)-- (0.850, 1.160)-- (0.780, 1.176)-- (0.700, 1.183)-- (0.645, 1.125)-- (0.579, 1.039)-- (0.518, 0.986)-- (0.438, 0.956)-- (0.343, 0.967)-- (0.289, 1.049)-- (0.249, 1.117)-- (0.195, 1.176)-- (0.125, 1.192)-- (0.030, 1.208)-- (-0.040, 1.220)--cycle,gray); [/asy] (A) $L_\text{A} > L_\text{B} > L_\text{C}$ (B) $L_\text{C} > L_\text{B} > L_\text{A}$ (C) $L_\text{B} > L_\text{C} > L_\text{A}$ (D) $L_\text{B} > L_\text{A} > L_\text{C}$ (E) The relationship between the magnitudes is different at various instants in time.