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Question: i need help with my assignment stuck on thesethe sketch...

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I need help with my assignment stuck on these

The sketch shows a painter’s scaffold in mechanical equilibrium.  The person in the middle weights 200 N, and the tensions in each rope are 160 N. What is the mass of the scaffold ?. (assume: g = 9.81 m/s2)

 

 

 

 

 

(a) 13 kg 

(b) 12 kg Answer

(c) 15 kg 

(d) 20 kg 

(e) 22 kg 

(f)  11 kg 

 

 

2.    An object is undergoing constant acceleration of 10 m/s2. If the object started with a velocity of 12 m/s, what is its velocity after 10 s ? 

 

(a) 100 m/s 

(b) 111 m/s 

(c) 108 m/s 

(d) 112 m/s Answer

(e) 115 m/s 

(f)  125 m/s  

 

3.    Find the magnitude of the resultant vector by adding two vectors in the following diagram: 

 

A  = 12 m 

B  = 6 m 

 

(a) 2 m 

(b) 8 m 

(c) 6 m Answer

(d) 1 m 

(e) 4 m 

(f)  5 m 

 

4.      A car has a velocity of 20 m/s after 1 min. The car increases its velocity uniformly for 30 s. After this time if has a velocity if 50 m/s. What is the car’s acceleration in this time period ? 

 

(a) 1.0 m/s2 Answer

(b) 0.8 m/s2

(c) 0.5 m/s2

(d) 1.2 m/s2

(e) 1.8 m/s2

(f)  2.0 m/s2

 

5.      A 10 kg block on a smooth frictionless surface is being pushed with two forces of 25 N and 10 N as show on diagram. What is the acceleration of the block ? 

 

 

 

(a) 3.0 m/s2

(b) 3.5 m/s2 Answer

(c) 2.5 m/s2

(d) 1.0 m/s2

(e) 1.5 m/s2

(f)  5.0 m/s2

6.      An astronaut has a weight of 500 N on the Earth. What is his/her weight on the planet with g = 0.65 m/s2.  (assume: g = 9.81 m/s2 for the acceleration due to gravity on the Earth).

 

(a) 20 N 

(b) 33 N Answer

(c) 24 N 

(d) 12 N 

(e) 35 N 

(f)  29 N 

 

 

4.      A ball is thrown straight up with an initial speed of 50 m/s. What is the maximum height the ball will reach ?. (assume: g = 9.81 m/s2).

 

 

(a) 115 m 

(b) 121 m 

(c) 132 m 

(d) 127 m 

(e) 123 m Answer

(f)  135 m 

 

 

 

 

 

5.      Determine the magnitude of the x-component of the force due to gravity on the 75kg-block if the following incline is frictionless (see picture below).  (assume: g = 9.81 m/s2).

 

 

 

 

(g) 550 N 

(h) 600 N 

(i)   605 N 

(j)   625 N 

(k) 603 N 

(l)   584 N 

 

6.      A = 3i – 2and B = -2i +5j. Find the direction of the vector C = A + B

 

(a) East 18.4 North 

(b) North 18.9 East 

(c) North 18.4 East 

(d) East 18.9 North 

(e) East 18.2 North 

(f)  North 18.2 East 

 

 

 

 

7.      When two horizontal forces are exerted on a cart, 800 N forward and 400 N backward, the cart undergoes acceleration. What addition force is necessary to produce nonaccelerated motion ?.  

 

(m)        150 N acting forward 

(n) 150 N acting backward 

(o) 400 N acting forward 

(p) 400 N acting backward 

(q) 200 N acting backward 

(r)  200 N acting backward 

 

8.      The following two blocks are pulled along a smooth frictionless surface. 

Find the tension in the rope between two blocks. 

 

 

 

(s)  10 N 

(t)   15 N 

(u) 20 N 

(v) 25 N 

(w)         30 N 

(x) 18 N 

 

 

 

 

9.      In the following system, determine the time for the 27 kg mass to reach the ground if it is released from rest. (assume: g = 9.81 m/s2).

 

 

(a) 0.55 s 

(b) 0.50 s 

(c) 0.58 s 

(d) 0.60 s 

(e) 0.45 s 

(f)  0.15 s 

 

10.  A boy walks 155 m at a speed of 3.5 m/s and then runs for 100 m at 8.2 m/s along a straight line. Calculate his average velocity. 

 

(a) 3.0 m/s 

(b) 4.5 m/s 

(c) 4.0 m/s 

(d) 2.5 m/s 

(e) 1.0 m/s 

(f)  12.0 m/s 

 

 

 

11.  A boat can accelerate from 2 to 21 km/h in 10 s. How far has the boat travelled in this time ? 

 

(a) 32 m 

(b) 30 m 

(c) 12 m 

(d) 25 m 

(e) 35 m 

(f)  22.5 m 

 

12.  A Porsche travelling at a constant velocity of 32 m/s passes a Mini parked on the side of the road. When the Porsche is 50 m ahead, the Mini starts accelerating uniformly at 3.5 m/s2. How fast is the Mini travelling when it reaches the Porsche ?. 

 

(a) 36 m/s 

(b) 45 m/s 

(c) 12 m/s 

(d) 69 m/s 

(e) 78 m/s 

(f)  112 m/s 

 

 

 

 

 

 

13.  Three vectors are given by A = 3iB = -1i +1j and C = 4j. Find the magnitude of the resultant vector. 

 

(a) 6.3 

(b) 5.4 

(c) 5.0 

(d) 2.3 

(e) 1.1 

(f)  0.5 

 

14.  A car has an initial velocity of 2.5 m/s. After displacement of 15 m, its velocity becomes 5.0 m/s. Find the acceleration of the car. 

 

(y) 0.525 m/s2

(z) 0.625 m/s2

(aa)       0.425 m/s2

(bb)       0.225 m/s2

(cc)       0.125 m/s2

(dd)       0.825 m/s2

 

 

 

 

 

 

 

 

 

15.  A 25 kg hanging object is connected by a light, inextensible cord over a light, frictionless pulley to a 3.2 kg block that is sliding on a flat table. Assuming a smooth frictionless surface of a flat table find the tension in the string. (assume: g = 9.81 m/s2).

 

(a)   28 N 

(b)   27 N 

(c)   25 N 

(d)   12 N 

(e)   20 N 

(f)    15 N 

 

19. An object moving in a straight line has the displacement-time graph shown. Find the average velocity for the trip. 

 

 

(a) 2.2 m/s 

(b) 1.2 m/s 

(c) 1.5 m/s 

(d) 0.0 m/s 

(e) 12.2 m/s 

(f)  16.0 m/s 

 

 

 

 

20. A 1,300 kg car accelerates uniformly from rest to 60km/h over a distance of 40 m. How much force is being applied by the engine to do this ?. 

 

(a) 4.5 ·103 N 

(b) 4.0 ·103 N 

(c) 3.5 ·103 N 

(d) 3.0 ·103 N 

(e) 1.5 ·103 N 

 

(f)  1.0 ·103 N      

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