Train moving with speed of \( (40 \mathrm{~m} / \mathrm{s}) \) the driver have resorted to the use of brakes to reduce the speed of the train movement by rate \( \left(-2 \mathrm{~m} / \mathrm{s}^{2}\right) \) Calculate: a) The amount of time it takes for the train even stops completely. b) The amount of distance traveled since the train began braking until it stops

24. Let \( |\vec{A}|=150 N \) and the vector \( \vec{A} \) makes an angle of \( 60^{\circ} \) with the positive y axis. Let P be the scalar projection of \( \vec{A} \) on to the xz plane and it makes an angle of \( 30^{\circ} \) with the positive x axis. Express vector \( \vec{A} \) in terms of its rectangular \( (\mathrm{x}, \mathrm{y}, \mathrm{z}) \) components;

27. Two trains, 1 and 2 , have an equal mass of \( m=5,000 \mathrm{~kg} \) each. Train 1 is traveling with a speed \( n=15 \mathrm{~m} / \mathrm{s} \) before striking train 2 , which was at rest. If the two trains lock together as the result of the collision. What is their common speed immediately after collision?

3.33 • Uma canoa tem velocidade de \( 0,40 \mathrm{~m} / \mathrm{s} \) a sudeste em relação à Terra. A canoa se desloca em um rio que escoa a \( 0,50 \mathrm{~m} / \mathrm{s} \) para leste em relação à Terra. Determine o módulo, a direção e o sentido da velocidade da canoa em relação ao rio.

3.33 • Uma canoa tem velocidade de \( 0,40 \mathrm{~m} / \mathrm{s} \) a sudeste em relação à Terra. A canoa se desloca em um rio que escoa a \( 0,50 \mathrm{~m} / \mathrm{s} \) para leste em relação à Terra. Determine o módulo, a direção e o sentido da velocidade da canoa em relação ao rio.

must be the charge of a Figure \( 23-40 \) shows a section of a \( R=3.00 \mathrm{~cm} \), with a charge per unit length of \( \lambda=2.00 \times 10^{-8} \mathrm{C} / \mathrm{m} \). What is the magnitude \( E \) of the electric field at radial distance (a) \( r=R / 2.00 \) and (b) \( r=2.00 R \) ? (c) Graph \( E \) versus \( r \) forthe range \( r=0 \) to 2.00R.