Let's assume you have a mass of 75 kg and your jeep has a mass of 1500 kg. How much greater is the force of gravity on the jeep?
Answers
Answer:
instant. PSYW
Answer: 6.6 m/s/s, up
There are two forces acting upon the skydiver - gravity (down) and air resistance (up). The force of gravity has a magnitude of m•g = (72 kg) •(9.8 m/s/s) = 706 N. The sum of the vertical forces is
∑Fy = 1180 N, up + 706 N, down = 474 N, up
The acceleration of the skydiver can be computed using the equation ∑Fy = m•ay.
ay = (474 N, up) / (72 kg) = 6.6 m/s/s, up
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50. A 5.20-N force is applied to a 1.05-kg object to accelerate it rightwards across a friction-free surface. Determine the acceleration of the object. (Neglect air resistance.) PSYW
Answer: 4.95 m/s/s, right
Upon neglecting air resistance, there are three forces acting upon the object. The up and down force balance each other and the acceleration is caused by the applied force. The net force is 5.20 N, right (equal to the only rightward force - the applied force). So the acceleration of the object can be computed using Newton's second law.
a = Fnet / m = (5.20 N, right) / (1.05 kg) = 4.95 m/s/s, right
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51. A 5.20-N force is applied to a 1.05-kg object to accelerate it rightwards. The object encounters 3.29-N of friction. Determine the acceleration of the object. (Neglect air resistance.) PSYW
Answer: 1.82 m/s/s, right
Upon neglecting air resistance, there are four forces acting upon the object. The up and down forces balance each other. The acceleration is rightward since the rightward applied force is greater than the leftward friction force. The horizontal forces can be summed as vectors in order to determine the net force.
Fnet = ∑Fx = 5.20 N, right - 3.29 N, left = 1.91 N, right
The acceleration of the object can be computed using Newton's second law.
ax = ∑Fx / m = (1.91 N, down) / (1.05 kg) = 1.82 m/s/s, right
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52. Determine the applied force required to accelerate a 3.25-kg object rightward with a constant acceleration of 1.20 m/s/s if the force of friction opposing the motion is 18.2 N. (Neglect air resistance.) PSYW
Answer: 22.1 N
There are four forces acting upon the object as shown in the free-body diagram at the right. The two vertical forces must balance since there is no vertical acceleration. Since the mass and the acceleration are known, the net force can be computed:
Fnet = m•a = (3.25 kg, right) • (1.20 m/s/s) = 3.90 N, right
Since the acceleration is to the right, the net force is directed to the right. Thus, the rightward force (applied force) must exceed the leftward force (friction force) by an amount equal to the 3.9 N. So the applied force can be computed.
Fapp = Ffrict + Fnet = 18.2 N + 3.90 N = 22.1 N