Question

question 1 -

Suppose that the Lo = 661 m main span of a steel bridge had no expansion joints. How much longer would the bridge be if the temperature increased from a cold winter at Tcold = –32 oC to a warm summer at Twarm = 30 oC? (The coefficient of linear expansion for steel is (alpha) α = 11 . 10-6 1/Co.)

question 2 -

A ball rolls along a surface, starting with an initial velocity of v_o = 59 m/s. Friction reduces the ball's final velocity to v_f = 12 m/s in a time of t = 2.7 s.
Determine the ball's acceleration a (type it as a negative number because it reduced the ball's velocity).

Answer 1

Q 1)

Here we have given that,

The initial length of the bridge at cold winter,

The temperature at cold winter,

Temperature at warm summer,

Linear coefficcient of expansion of the steel,

So,the final length of bridge at warm summer,

ie,

So,final length of the beam at warm summer,

Q2)

Here given that the initial velocity of the ball,

Due to the negetive work done by friction ofn the ball,its velocity reduces to final velocity,

The time taken for this change of velocty,

So,the acceleration of the ball,

So,here the acceleration of the ball,