1. What is the speed of a) O m/s object b) 10 m/s from a height of 10 m just bef

Question

1. What is the speed of a) O m/s object b) 10 m/s from a height of 10 m just before it hits the ground? d) not enough info given c)20 m/s 2. What is friction inth a) 9.8 m/s ration of the system of the following figure system and masses are given in kg.45 m/s There is no einone of these b) 4.9 m/s c) 19.6 m/s )2.45 m/s 3. What is the tension in the cord of question 2? a)9.8 N b)4.9N 6N d) 2.45 N enone of these 4. What is top? a)10N by a 20 N object resting on a table, if a 10 N object is placed on its 30N 40 N n these 5. Two blocks of equal mass m, - ma 1-kg are attached by a string to undergo a free fall. What is the tension in the connecting string? lONb)1-N c)O.SN d) 2-N e) none of these 5. What is the net force experienced by m of mass 1-kg if ma has a mass of 4-kg and a 100-N force is acting as shown? a) o-N 6. A ball opposite direction. How much has the ball's momentum changed? mi b)20-N e) none of these c)50-N d) 100-N g a momentum of 3-Kg(m's) bounces off a wall and carries a momentum of 2 Kg(m/s) in a) o e) 8 Kg(m/s) b) 2 Kg(m/s) 7. Ignoring the air resistance, second? a) o d) depends on how fast it is moving approximately how much does the momentum of a falling ball change in a b) 10 Kg(m/s) e) not enough information given 8. What is the Kg(m/s), punching a) 500 N average force that a bullet exerts on a wooden door by striking it with a momentum of 50 a hole, and emerging 0.1 second later with a momentum of 45-Kg(m/s) b) 4500 N d) 9500 N e) none of these c) 5000 N 9. What is the x-component of a vector of magnitude 200 having a y-component of 100? a) 100 b) 150 c)173 d) 193 e) none of these 10. What are the x and y-components of the vector shown in the following diagram? a) 4,5 b) 2, 5 d)5.2

Explanation / Answer

1. in vertical, a = 9.8 m/s^2

vf^2 - vi^2 = 2 a d

v^2 - 0^2 = 2(9.8)(10)

v = 14 m/s Ans(e) None of these

2. on 1: 1g - T = 1 a

on 4: T = 4 a

1g = (1 + 4)a

a = 9.8/5 = 1.96 m/s^2

Ans(e) None of these

3. T = 4x 1.96 = 7.84 N

Ans(e)

4. for equilibrium, a = 0

F_net = m a = 0

Ans(e)

5. both are free falling with same acc a = 9.8 m/s^2

so T = 0 Ans(a)

5. a = F_net / m = 100 / (1 + 4) = 20 m/s^2

F_net = ma = 1 x 20 = 20 N  

Ans(b)

6. change in momentum = pf - pi

= 2 - (-3)

= 5 kg m/s Ans(d)

7. delta(V) = a t = g x 1 = g

change in momentum = m deltav = m g = weight

Ans(c)

8. impulse = change in momentum = F t

50 - 45 = F(0.1)

F = 50 N Ans(e)

9. vx^2 + vy^2 = v^2

vx^2 + 100^2 = 200^2

vx = 173 m/s Ans(c)

10. vx = 5 unit (along x axis)

vy = 2 unit (along y axis)

Ans(d)

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