The position of an object moving along a line is given by #p(t) = 2t - cos(( pi )/4t) #. What is the speed of the object at #t = 7 #? Physics 1D Motion Displacement and Velocity 1 Answer ali ergin May 4, 2016 #v(7)=(16-sqrt2 pi)/8# Explanation: #v(t)=d/(d t) p(t)# #v(t)=d/(d t)(2t-cos(pi/4t))# #v(t)=2+pi/4sin(pi/4t)# #v(7)=2+pi/4sin(pi/4*7)# #v(7)=2+pi/4*(-sqrt2/2)# #v(7)=2-(sqrt2pi)/8# #v(7)=(16-sqrt2 pi)/8# Answer link Related questions What is the difference between distance and displacement? Is displacement directly proportional to velocity? How does average velocity differ from instantaneous velocity? How can I calculate the change of velocity? How do speed and velocity differ from each other? How do velocity and acceleration differ? How do displacement and distance differ? Can displacement be negative? Can velocity be zero if accelerating? Explain why displacement is a vector quantity? See all questions in Displacement and Velocity Impact of this question 1143 views around the world You can reuse this answer Creative Commons License