Physics 1100 (Fall16) Exam#1A, Name__________________________, ID#______________, Score________
[Note: 5% for each question]
1. (1D Kinematics) A bird flies from the Manhattan Beach to Brooklyn College along the Ocean Avenue. It flies with a
constant speed for 4 km for 10 minutes arriving at Ave. Z. It than accelerates its speed from Ave. Z to Ave. M at
which the bird’s traveling speed is 10 m/s. From Ave. M to Brooklyn College, the bird’s speed decreases from 10 m/s
to zero when it arrives at Brooklyn College, traveling another 5 km.
(a) What is the bird speed in between Manhattan Beach and Ave. Z? Ans. _______6.7 m/s______
(b) What is value of acceleration from Ave. Z to M if the distance between the two avenues is 6 km?
Ans. _________4.63e-3 m/s2_______
(c) How long does the bird fly from Ave. Z to Ave. M? Ans.__713 s______
(d) What is the value of de-acceleration between Ave. M and Brooklyn College? Ans. __0.01 m/s2______
(e) How long does the bird fly from Ave. M to Brooklyn College? Ans._____1000s_________
2. (2D kinematics) A ball is thrown from a 60.0-m high building top with a speed of 20 m/s in an angle of 30 degree
from horizontal and lands on the ground. Ignore air resistance and use g = 10 m/s2.
(a) What is horizontal initial velocity? Ans. __17.3 m/s_________
(b) How long does the ball take to reach to the maximum height? Ans.___1 s________
(c) What is the maximum height the ball can reach above the ground? Ans. ___65 m____
(d) How far the ball can reach away from the building when it lands? Ans._____80 m____
(e) What is the vertical component of the velocity just before the ball hits the ground? Ans. ___36 m/s_____
(f) What is the horizontal speed just before it hits the ground? Ans. ____17.3 m/s_________
(g) What is the magnitude of ball’s final velocity just before it hits the ground? Ans. ___40 m/s___________
3. (Newton’s Laws, gravitation, normal force, and friction force) A skier with a mass of 65 kg is sliding down a slope
(25 degree from horizontal level). The coefficient of kinetic friction is 0.08. Use g = 10 m/s2. Find: (a) the gravitation
force on the skier, Ans. ___650 N_________ (b) the normal force on the skier, Ans. ___589 N_______ (c) the value
of acceleration parallel to the slope, Ans. _____3.5 m/s2_____ (d) the acceleration perpendicular to the slope, Ans.
___0____ (e) the static coefficient of friction so that the skier has zero acceleration. Ans. ____0.47________
4. (Newton’s Laws, tension) A 300-kg horse is pulling a heavy 200-kg sled on a flat snowy ground through a rope
connection and traveling with a speed of 5 m/s. The ground provides a force of 1300 N to the horse in parallel to the
ground. The friction force on the sled is 150 N and no friction force acting on the horse. Find: (a) the acceleration of
horse-sled system, Ans.____2.3 m/s2______and (b) the tension in the rope, Ans._____610 N_________.
Kinematics
v = v0 + at
x = x 0 + v 0t +(1/2)at 2
v2 = v02 + 2a(x − x0)
Newton’s Laws
V0 remains with Fnet = 0
Fnet = ma
F1 = - F2