PHYS$-110$

Practice problem sheet for Chapter $2($PPS$-02)$

Problems to be done in class

Suppose an object moves from an initial position of $-6m_{{?}_{?}}$ to a final position of $-7m.$ What is its displacement?

A car starts from Providence and reaches Boston in $1\mathrm{.}5$ hours. It then returns to Providence in $1$ hour. Assuming that the distance between Providence and Boston is $50$ miles,

a$)$ what is the speed of the car when it travels from Providence to Boston?

b$)$ what is the speed of the car when it travels from Boston to Providence?

c$)$ What is the velocity of the car for the round trip?

How much time does a car traveling at a speed of $50mph$ take to cover a distance of $70km?$

A ball thrown at a brick wall bounces directly back with the same speed it had when it struck the wall. Has the velocity of the ball changed? Explain

Which of the following statements is true?

a$)$ Velocity is zero necessarily means acceleration is zero

b$)$ Acceleration is zero necessarily means velocity is zero

c$)$ Position is zero necessarily means acceleration is zero

d$)$ None of the above

True or false: The acceleration of a slow moving object can be more than that of a fast moving object

A runner goes from a speed of $0\frac{m}{s}$ to a speed of $8\frac{m}{s}$ in $2$ seconds. $($a$)$ What is his acceleration?

$($b$)$ If the same runner comes to rest in $3$ seconds, what is his acceleration?

A motorist traveling on the highway with a speed of $25\frac{m}{s}$ applies brakes on the car which results in an acceleration of $-5\frac{m}{s^2}.$ How much time does it take for the car to come to a halt?

A stone dropped from the top of a building hits the ground in $3$ seconds. What is the final velocity of the stone?

Consider the position$-$time graph shown below:

a$)$ What is the velocity at $t=30s?$

b$)$ What is the velocity at $t=50s?$

c$)$ What is the acceleration at $t=30s?$

d$)$ What is the acceleration at $t=50s?$ position $($m$)$