True or false : in the theory of relativity , space and time are merged into space time meaning that time is treated as the 4th dimension

Rohit is trying to tune an instrument

Asled is being held at rest on a slope that makes an angle θ with the horizontal. after the sled is released, it slidesa distance d1 down the slope and then covers the distance d2 alongthe horizontal terrain before stopping. find the coefficient ofkinetic friction μk between the sled and the ground, assumingthat it is constant throughout the trip. find the coefficient of kinetic frictionμk. express your answer in terms of someor all of the variables d1, d2, and θ.

Acar starts from rest at a stop sign and reaches a velocity of 25 m/s w in 4 seconds. determine the acceleration of the car. question 3 options: a) 6,25 m/s2 b)6.25 m/s c)100 m/s2 d)100 m/s