(i) The distance \( d \) travelled by a ball is proportional to the square the time taken, \( t \). After 4 seconds the ball has travelled 40 n (i) Find a formula linking \( d \) and \( t \). (ii) Find the distance travelled after 7 seconds.

\( \left. \begin{array} { c } { L = L _ { 0 } \sqrt { 1 - \frac { v ^ { 2 } } { c ^ { 2 } } } } \\ { = 90 \sqrt { 1 - \frac { ( 0.8 C ) ^ { 2 } } { ( 3 \times 10 ^ { 8 } ) ^ { 2 } } } = 54 m } \end{array} \right. \)

Arus listrik sebesar 5 mA mengalir pada suatu kawat penghantar selama 0,1 sekon. Berapa besar muatannya ?

(b.) student : (1) My Day 9. An airplane starts from rest and accelerates at a constant rate of \( 3.00 \mathrm{~m} / \mathrm{s}^{2} \) for 30.0 s before leaving the ground. a. How far did it move? b. How fast was it going when it took off? 10. A brick is dropped from a high scaffold. a. What is its velocity after 4.0 s ? b. How far does the brick fall during this time? 11. A tennis ball is thrown straight up with an initial speed of \( 22.5 \mathrm{~m} / \mathrm{s} \). It is caught at the same distance above the ground. a. How high does the ball rise? b. How long does the ball remain in the air?

Per stimare lo spessore di una moneta da 10 centesimi di misura con un righello l'altezza della pila di monete ot- tenuta. La misura e e \( (2,9 \pm 0,1) \mathrm{cm} \), dove \( 0,1 \mathrm{~cm} \) è la sen- sibilità del righello. - Stima lo spessore della moneta. \( \quad[(1,93 \pm 0,07) \mathrm{mm}] \)

A block weighing 500 N is at the point of just starting to move down a rough inclined plane when supported by a force of 200 N acting parallel to the plane in an upward direction. The same block, on the same rough inclined plane, is on the verge of moving up the plane when pulled by a force of 300 N acting parallel to the plane. Compute the inclination of the plane and the coefficient of friction between the inclined plane and the block.