The acceleration of a particle moving along the x-axis at time t is given by a(t)=6t−2. If the position is 10 when t=1, then which of the following could be the function for position x(t)=?(A) 9t2+1(B) 3t2−2t+4(C) t3−t2+4t+6(D) t3−t2+9t−20(E) 36t3−4t2−8t+5
Q. The acceleration of a particle moving along the x-axis at time t is given by a(t)=6t−2. If the position is 10 when t=1, then which of the following could be the function for position x(t)=?(A) 9t2+1(B) 3t2−2t+4(C) t3−t2+4t+6(D) t3−t2+9t−20(E) 36t3−4t2−8t+5
Integrate acceleration for velocity: To find the position function x(t), we need to integrate the acceleration function a(t)=6t−2. The integral of acceleration gives us the velocity function v(t).
Find constant for velocity: The indefinite integral of a(t) with respect to t is: ∫(6t−2)dt=3t2−2t+C, where C is the constant of integration for the velocity function.
Integrate velocity for position: To find the constant C, we need an initial condition for velocity. Since we are not given the initial velocity, we cannot find the exact value of C at this step. We will proceed to find the position function x(t) and use the given initial position to find the constant for the position function.
Find constant for position: Now we integrate the velocity function to get the position function x(t):∫(3t2−2t+C)dt=t3−t2+Ct+D, where D is the constant of integration for the position function.
Use initial position to find constants: We are given that the position is 10 when t=1. We use this condition to find D: x(1)=13−12+C⋅1+D=101−1+C+D=10C+D=10Since we do not have the value of C from the velocity function, we cannot find the exact values of C and D. However, we can compare the structure of the resulting position function with the given options to see which one could potentially match.
Compare position function with options: We compare the structure of the position function t3−t2+Ct+D with the given options:(A) 9t2+1 does not match because it lacks the t3 term.(B) 3t2−2t+4 does not match because it lacks the t3 term and has the wrong coefficient for the t2 term.(C) t3−t2+4t+6 has the correct t3 and t2 terms, but we cannot confirm the coefficients for the t and constant terms without the initial velocity.(D) 9t2+10 has the correct t3 and t2 terms, but again, we cannot confirm the coefficients for the t and constant terms without the initial velocity.(E) 9t2+14 does not match because it has incorrect coefficients for the t3 and t2 terms.
Analyze options for correct function: Since options (C) and (D) have the correct t3 and t2 terms, we need to determine which one could be the correct position function based on the given initial position x(1)=10. For option (C): x(1)=13−12+4⋅1+6=1−1+4+6=10. This matches the given initial condition. For option (D): x(1)=13−12+9⋅1−20=1−1+9−20=−11. This does not match the given initial condition.
Analyze options for correct function: Since options (C) and (D) have the correct t3 and t2 terms, we need to determine which one could be the correct position function based on the given initial position x(1)=10. For option (C): x(1)=13−12+4⋅1+6=1−1+4+6=10. This matches the given initial condition. For option (D): x(1)=13−12+9⋅1−20=1−1+9−20=−11. This does not match the given initial condition.Therefore, the correct function for the position x(t) is option (C) t3−t2+4t+6, as it matches the structure of the position function we derived and satisfies the initial condition x(1)=10.
More problems from Relate position, velocity, speed, and acceleration using derivatives