Question

Conceptual Multiple-Choice Questions (25% total, 5% each) Circle the best answer. No partial credit is awarded in these questions. 1. An object's position over time is given by x = bt* + ct, where x is position, t is time, and b and care constants. What are the base SI units of b and c? a. [b] = m and [c] = m b. [b] = m/s and [C] = m c. [b] = m/s2 and [C] = m/s d. [b] = m/s3 and (c) = m/s2 e. [b] = m/s* and [c] = m/s2 2. When it is appropriate to make an approximation in a model, like neglecting air resistance in projectile motion? a. If it says to in the book b. Whenever it makes a calculation easier c. If it makes a calculation easier and your answer should be close enough to suit your purposes. d. Any approximation is impermissible, since it makes your answer incorrect 3. A car makes a left turn at a constant speed. What is the direction of its acceleration vector as it turns as measured by the reference frame of the road? (a, Directly to the car's left b. Directly to the car's right c. Directly forward d. Directly backward e. Forward and to the left f. Backward and to the left g. Forward and to the right h. Backward and to the right 4. A car makes a left turn while speeding up. What is the direction of its acceleration vector as it turns as measured by the reference frame of the road? a. Directly to the car's left b. Directly to the car's right c. Directly forward d. Directly backward e Forward and to the left f. Backward and to the left g. Forward and to the right h. Backward and to the right 5. In the rest frame of the ground a person stands still, and a car moves in the +x direction. What direction is the velocity of the person, as measured by the rest frame of the car? a. +x direction b. -X direction c. +y direction d. -y direction e. +z direction f. -z direction g. No direction, the person is not moving in the rest frame of the car.

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Answer 1

same as dimensions of a 1 x otot ct? - Dimensions of btt should be [btt] = [2 ] [6] [t'] = 1 [6] [t? Je [L] * Si unit of bei mist - Dimts similarly [at²] = 2 => [c] [72] = z) [C] LT - SI units of ez m/s2 2) Making on an approximation leads to some error 1 in the final answers, however it making an 1. apporoximation may greatly simplity your cale So if the approximation simplies calculation thout affecting the accuracy much we shall use it. 3) so as shown at a turn is a of - a circle 2 is a arc circular . .. acca will be towards the centre Die directly towards car's left. 4) In this case there will be an additional forward acceleration as the speed is abo increasing afort - from the centripetal acch towards left.. 5) The car is moving din tx direction. To an - observer in the car person on ground would appear 19 to move directions in ax directim I) relocity in ax