#### Transcript Slide 1

```A bicycle has a mass of 13.1 kg, and its
rider has a mass of 81.7 kg. The rider is
pumping hard, so that a horizontal net
force of 9.78 N accelerates them. What is
the acceleration?
Scientists are experimenting with a type of
gun that may eventually be used to fire
payloads directly into orbit. In one test,
this gun accelerates a 5 kg projectile from
rest to a speed of 4000 m/s. The net force
accelerating the projectile in 4.9 x 105 N.
How much time is required for the
projectile to reach top speed?
Two forces FA and FB are applied to an
object whose mass is 8.0 kg. The larger
force is FA. When both forces point east,
the object’s acceleration has a magnitude
of 0.5 m/s2. However, when FA points
east and FB points west the acceleration
is 0.4 m/s2 east. Find FA and FB.
Two forces act on the 5 kg block shown in
the drawing. The magnitudes of the forces
are F1 = 45 N and F2 = 25 N. What is the
horizontal acceleration of the block?
The speed of a bobsled is increasing,
because it has an acceleration of 2.4 m/s2.
At a given instant in time, the forces
resisting the motion, including kinetic
friction and air resistance, total 450 N.
The mass of the bobsled and its riders is
270 kg. What is the force providing the
push on the bobsled?
W1 = 55 N, W2 = 35 N, W3 = 28 N. What is
the magnitude of the normal force that the
table exerts on box 1?
The drawing show a
circus clown who
weighs 890 N. The
coefficient of static
friction between his feet
and the ground is 0.53.
With what force must he
pull down on the rope to
pull his feet out from
under himself?
A penguin slides at a constant velocity of
1.4 m/s down an icy incline. The incline
slopes above the horizontal at an angle of
6.9o. At the bottom of the incline, the
penguin slides onto a horizontal patch of
ice. The coefficient of kinetic friction
between the penguin and the ice is the
same for the incline as for the horizontal
patch. How much time is required for the
penguin to slide to a halt after entering the
horizontal patch of ice?
The moons period is 27 d 8 h and the
radius of its orbit is 383438 km. What is
the mass of the Earth?
A satellite is in a circular orbit around and
unknown planet. The satellite has a speed
of 1.7 X 104 m/s, and the radius of the
orbit is 5.25 X106 m. A second satellite
also has a circular orbit around this same
planet. The orbit of this second satellite
has a radius of 8.6 X 106 m. What is the
orbital speed of the second satellite?
```